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Recovering a Wrecked RAID

Zonk posted more than 7 years ago | from the undead-data dept.

Data Storage 175

Dr. Eggman writes "Tom's Hardware recently posted an article specifying how the professionals at Kroll Ontrack recover data from a RAID array that has suffered a hard drive failure, allowing for recovery of even RAID 5 arrays suffering two failures. The article is quick to warn this is costly, however, and points out the different types of hard drive failures that occur, only some of which are repairable. Ultimately the article concludes that consistent backups and other good practices are the best solution. Still, it provides an interesting look into the world of data after death."

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RAID5. (0)

Anonymous Coward | more than 7 years ago | (#18124414)

Any fanboys or critics of RAID5 here?

Re:RAID5. (3, Informative)

Anarke_Incarnate (733529) | more than 7 years ago | (#18124452)

RAID 5 is great, though expensive when done right. RAID 6 is better, though has less performance, as well as additional cost. Many controllers will not do RAID 6, and you lose 2 drives to parity. If your data is truly critical, you should have backups done VERY often, as well as a RAID 50. This way you are far less likely to lose data, though you have to have a stripe of at least 3 drives, in a mirror. This requires at minimum, 6 drives. There are also VRAIDs, which allow for you to lose drives until you hit the watermark of your data. This technology is usually reserved for SAN systems.

Re:RAID5. (4, Insightful)

networkBoy (774728) | more than 7 years ago | (#18124568)

For DB's and home use a mirror set is usually best. For homes because it is simple, for DB servers because it is fast.
My home setup is a pair of 300 gig drives in a mirror, with another 1.6TB for other storage. Stuff that is important is on the mirror, and is differentially backed up to DVD regularly.
Stuff on the mass array is available in original form (my DVD and CD library that's been ripped) or is backed up whenever it changes, which is not often (my code library, for example). Active code and my wife's thesis are on the raid. Supporting documents for the thesis are on DVD and mass storage, as is old code projects that I may borrow from for functionality in a new project. The old project (and likely several versions of it) are off on DVD in a safe deposit box, with the rest of my backups.

Safe deposit boxes are awesome. I have one that can store 600 cds in cake boxes and it only costs $120/year. Dirt cheap for climate controlled fireproof storage.

Re:RAID5. (1)

swb (14022) | more than 7 years ago | (#18124960)

Mirroring is an expensive waste of disk space unless you really need the fast write times.

I think a 4 disk RAID-5 is a better sweet spot, since you lose less storage to parity/recovery data and it seems cheaper to buy 4x smaller drives than 2x larger drives. 2 300GB disks looks around $200 and 4x 120GB disks is around $220, but you end up with 60GB more space for the $20.

Re:RAID5. (2, Informative)

endoftheroadmatt (695815) | more than 7 years ago | (#18125132)

It's not that expensive with the price of drives these days. The nice thing about a mirror is that if your controller (or something else if you have a software raid) dies you can mount one of the drives on its own. After dealing with a failed controller, I'm glad to fork out a little more money for the piece of mind.

Re:RAID5. (1)

networkBoy (774728) | more than 7 years ago | (#18125304)

Plus the controller is cheaper, saving the 60 gig worth of money.

Re:RAID5. (1)

lukas84 (912874) | more than 7 years ago | (#18125686)

Depends on what we're talking about.

For SMB customers, i usually use 2 seperate RAID1 sets.

Why? Because SMB customers usually use their stuff looong beyond the expected lifetime, and don't have any support contracts. If a RAID controller dies, you're usually in trouble - because a replacement without a contract costs more than a new machine. If you use RAID1, you usually don't have to worry about that, since you (usually) can just plug them into a normal controller.

Re:RAID5. (1)

swb (14022) | more than 7 years ago | (#18126808)

How often do you see raid controllers actually fail? I'm not sure I've ever seen one fail since I started working with them in the early 90s.

Re:RAID5. (1)

Anarke_Incarnate (733529) | more than 7 years ago | (#18125794)

Mirrors have slower writes and faster reads. This is because the controller can pull different chunks of data from both/all hard drives. The writes are not faster as there has to be twice as many. Striping has faster writes but no tolerance for failure

Re:RAID5. (3, Informative)

Intron (870560) | more than 7 years ago | (#18125976)

With the two drives on separate channels, mirrored writes can be done in parallel.

Re:RAID5. (4, Insightful)

drinkypoo (153816) | more than 7 years ago | (#18124572)

RAID 50? Why not RAID 10? If you're already mirroring, the RAID 5 will probably not afford you much additional protection, and it has the effect of making writes slower.

Re:RAID5. (1)

grommit (97148) | more than 7 years ago | (#18125162)

Because maybe you've got a dozen drives in the array. RAID 10 would be a serious hit on capacity while RAID 50 wouldn't be so bad.

Some file storage doesn't need to be super fast but you need a lot of it and you need reliability. Hence, RAID 50. You'll learn that the first time you have a budget on a hardware deployment.

Re:RAID5. (1)

wirelessbuzzers (552513) | more than 7 years ago | (#18125574)

RAID 50 is pretty fast for reads, and not very reliable. Fail the wrong two drives, and down it goes. With a dozen drives in the array, that's getting pretty scary: odds are low, but still significant, that if one drive fails, another will fail before you can resilver, and almost a half chance that it's the wrong one.

I'd go for RAID 6 or RAID 10 for a big storage cluster, if it needed to be decently reliable. RAID 10 is a lot smaller, but it's faster and about 5 times less likely to fail than RAID 50. RAID 6 is about as fast as RAID 50, has the same storage capacity, and is much more reliable, but you'll probably need a RAID controller.

The easy way to fix a wrecked raid (2, Funny)

StreetStealth (980200) | more than 7 years ago | (#18126072)

Really, a wrecked raid can be fixed pretty easily if you have enough warlocks to get everyone a soulstone.

Re:RAID5. (1)

Dr. Eggman (932300) | more than 7 years ago | (#18124618)

Curiosity forces me to ask: If I'm looking into a series of cheap 80GB hard drives for $42, is it worth the extra ~$84 to go with a RAID 60, requiring 8 drives minimum, rather than the 6 drive RAID 50? I ask because in recent research, I noted that with RAID 50, if you suffer two HD failures in the same stripe, the entire array goes out, but with the RAID 60, you have to lose 4 HD (literally half the array) before the array is unrecoverable. Do you or anyone else have some preformance comparisons between RAID 50 and RAID 60? What sort of software and/or hardware options does one have with each type?

Re:RAID5. (4, Insightful)

jandrese (485) | more than 7 years ago | (#18124900)

Guys, if you're doing regular backups and have a cold spare handy then RAID5 is typically more than enough. Two drive failures are exceedingly rare unless you have some sort of controller fault (and that will typically hit all of your drives anyway). Don't forget about the write penalty either, RAID 5 has a fairly stiff penalty, but RAID 6 is even worse. If you're talking about RAID5_0 or RAID6_0 you're almost certainly doing it wrong or planning for a day when you can't buy replacement hard drives (nuclear holocaust?).

To put it another way: What do you think your chances are of having a second drive failure in the few hours it takes you to replace the drive and rebuild it? Even if that does happen you just lose the data up until your last backup (a day at most).

Most professional installations I do are RAID1_0, because people are building the RAID array for the performance, not the cost. Since you're using crappy 80GB HDDs, I'm guessing you're going for cost, which makes it strange that you're thinking about a RAID6_0 solution at all (the controller alone won't be cheap for that). If you work the odds I think you'll find that it's just not worth it to build a RAID6_0, especially given the write penalty and complexity (complexity is your enemy with this, complexity means bugs, which can undermine your entire effort).

sorry, that's wrong... (2, Informative)

HalfOfOne (738150) | more than 7 years ago | (#18125930)

This is good reading: []

Short synopsis for those who don't want to read it: The rebuild process is intense enough to cause secondary failures in many more cases than you'd think. Because you haven't seen it yet is not indicative of the overall population, and sysadmins are payed to be prepared.

The rest of your post is arguable, but it's more a matter of opinion and practice than anything else.

Re:sorry, that's wrong... (1)

jandrese (485) | more than 7 years ago | (#18126890)

The conclusions from that article seem to contradict some of the sources. For instance, they talk about how there is no infant mortality, but then link to the Google study that shows that yes, there is infant mortality (although it may not be as strong as some people think). Infant mortality is not one of the things I've had much trouble with though, so YMMV.

I've never seen the second drive die during a rebuild (although this is typically RAID1_0, not RAID5), but that may be more a factor of the drives tend to work very hard regardless, so the rebuild is not much different from their normal usage pattern.

Re:RAID5. (1)

goarilla (908067) | more than 7 years ago | (#18125990)

what i always wanted to ask a guy who clearly knows a lot about this stuff is
what physical media do you recommend for regular snapshots/backups: tape archives, DVD's (it would take a hell lot of dvd's to backup 1 TB i think)
or just another machine (with or without RAID), NAS, SAN, ...?

Re:RAID5. (1)

jandrese (485) | more than 7 years ago | (#18126756)

Completely depends on your environment. Large tape changers (robots) are pretty much your only choice with big datacenters. For home use removable hard drives are often good enough, especially since most home users don't do offsite backups like they should. You can even used fixed hard drives for home use, depending on how much you value your data. DVD backups aren't worth it in my experiance, they're too finicky and streaming across multiple disks is a pain at best.

Re:RAID5. (0)

Anonymous Coward | more than 7 years ago | (#18126392)

And when the rebuild takes 14 hours? actually 24 considering the build to the hot spare is 10 hours ?

Re:RAID5. (0, Offtopic)

ashren (965884) | more than 7 years ago | (#18124508)

this is slashsot there are _always_ fan boys and critics

Long-winded advertisement^H^H^H^H^H^H^H^H article. (4, Insightful)

QuietLagoon (813062) | more than 7 years ago | (#18124590)

It takes far too many pages to say what could actually fit in a page or two.

Re:Long-winded advertisement^H^H^H^H^H^H^H^H artic (0)

Anonymous Coward | more than 7 years ago | (#18124726)

HTH [] .

But a great battle cry! (1)

Roadkills-R-Us (122219) | more than 7 years ago | (#18126762)

``Still, it provides an interesting look into the world of data after death.''

Death before data!!!

FOR THE LAST FREAKIN' TIME... (5, Insightful)

canUbeleiveIT (787307) | more than 7 years ago | (#18124606)

Never put all of your eggs in one little basket (RAID or otherwise)! For the love of God, if your data is critical, you need a backup *and* an offsite backup. At least one of each. There are no exceptions to this rule.

Re:FOR THE LAST FREAKIN' TIME... (4, Informative)

eln (21727) | more than 7 years ago | (#18124668)

That's true, but the most common cause of data loss on a RAID system that I've seen is when a disk fails, and people leave it there for days or even weeks without bothering to replace it.

When a disk fails in a RAID, it needs to be replaced IMMEDIATELY. A RAID system with a failed disk is a disaster waiting to happen. I've been in smaller shops that don't even have spare disks around. When a disk failed, they would order a disk at that point and have it shipped.

You should always have plenty of spare disks around, and you should replace disks as soon as they fail. A double disk failure is rare, but the longer you put off replacing a failed disk, the more likely it becomes.


Anonymous Coward | more than 7 years ago | (#18124850)

I sometimes have sudden long spurts of laziness. I currently have a RAID5 with a drive that faulted and is marked out of the array. I replaced the drive but after I turned the machine back on, I got too lazy to run the command to put the new drive into the array. It's been like this for two weeks, but every time I remember I'm not anywhere I can get to the machine to type the command to add the drive back in.

Thanks to your insensitive posting, I'll go home tonight after work and the whole array will be dead.

Re:FOR THE LAST FREAKIN' TIME... (2, Insightful)

BagOBones (574735) | more than 7 years ago | (#18126128)

I agree they must be replaced ASAP. However I don't keep drives on hand when my vendor can get a new disk to my desk within 4 hours of my call at no charge.


denobug (753200) | more than 7 years ago | (#18125198)

A double disk failure is rare, but the longer you put off replacing a failed disk, the more likely it becomes.

I run a RAID 1 array in my house. Recently I just experienced double disk failure about a month ago. Granted both disks are only a month old and are more than likely a manufacture's issue (Watch out Seagate users!), but I guess I'm the exceptions to the rule that both disks failed within days. Fortunately no important data was lost.


vadim_t (324782) | more than 7 years ago | (#18125864)

When running RAID-1, use disks of different brands for extra safety. Then they should be less likely to fail exactly at once.


Anonymous Coward | more than 7 years ago | (#18125722)

Warranty, service contracts, etc. Keep them up to date and configure monitoring.

With Microsoft Operations Manager and a valid 4 hour service contract we've never had a drive failed for more than 3 hours before it's been replaced.

Terminolgy update (2, Funny)

sasdrtx (914842) | more than 7 years ago | (#18126224)

When a disk fails in a RAID, it becomes an AID.

Or in the case of RAID-1, it becomes just an ID.


alex_guy_CA (748887) | more than 7 years ago | (#18125926)

Totally. I come home with a few GB of data from a photo shoot, and it goes onto the main drive on my computer. Then I back it up to TWO SEPARATE drives, not a RAID of two drives, two independent drives. Eventually, when the drive on my computer fills up, I transfer the files from there onto a DVD and bring it off site. Not only does this method protect me from drive failure, it protects me from user error. For example, if I am working on a photo, convert it to black and white and accidentally "save" instead of "save as," if I had RAID, I would still be out of luck. With my system, I can go to the other back-up and pull the unaltered file off. BTW I'm on a mac, and I use Deja Vu for my backups.

Software RAID (3, Insightful)

Kludge (13653) | more than 7 years ago | (#18124638)

People often poopoo software RAID (it is more of a pain to manage). But when it comes to recovery, it's what you want. You know the disk format and have the tools. Of course, you really shouldn't have to recover, you should keep good backups or another mirror if its that important.

Re:Software RAID (0)

Anonymous Coward | more than 7 years ago | (#18124898)

The point of RAID is not to lose ANY data so you HAVE to do the recovering step. With "good backups or another mirror" you can only recover a past snapshot.

Re:Software RAID (1)

mnmn (145599) | more than 7 years ago | (#18125202)

Ok I'm getting sick.

Backups are not a 'solution'. They are a 'backup solution' to the 'main solution'.

Of course one should keep backups, but I'm sick of it being called a solution to drive crashes.

I had a drive crash this morning (on a server that is fully backed up daily. And I've had to get another server started and serving DHCP and DNS simply because I needed the thing up and running FAST. The RAID system crashed. If a drive crashed and it was in a RAID system, the server will keep running. Now that's what I'd call a 'primary solution' to a drive crash rather than blurt out 'oh and regular backups is a good solution'. Only if you can backup once every minute and restore within 60 seconds.

Re:Software RAID (1)

Sancho (17056) | more than 7 years ago | (#18126898)

You're throwing around the word 'solution' without defining the real problem.

RAID is to keep the system running (except for that absurd RAID0 crap).
Backups are to mitigate data loss.

Now let's look at what the article was about. The title is "Recovering a Wrecked RAID". Why might you need to do this? To keep the system running? Not with what they're talking about. No, they're talking about recovering from a data loss where RAID is involved. Responding to this with, "Well, you should have kept backups. Then you wouldn't need the expensive and time consuming recovery solution," is absolutely an appropriate response.

Re:Software RAID (1)

darrylo (97569) | more than 7 years ago | (#18126264)

Agreed (for home use), and ZFS's raidz is the easiest. ;-)

Unfortunately, Solaris's IDE controller support sux. :-( If they only supported PCI-based IDE controllers, it would be soooo easy to create and maintain a RAID array using old hardware.

Gotta love Tom's articles (4, Insightful)

sjbe (173966) | more than 7 years ago | (#18124650)

Could these articles be any more annoying to read?

They painstakingly


pull data


off the


damaged drive

Printer Friendly (3, Insightful)

TubeSteak (669689) | more than 7 years ago | (#18124784) ry/print.html []

I don't know why TH has printer friendly pages that they don't ever link to.

Re:Printer Friendly (1)

hankwang (413283) | more than 7 years ago | (#18125076)

I don't know why TH has printer friendly pages that they don't ever link to.

Where did you find that link? If I follow it I'm redirected to the multi-page version.

Re:Printer Friendly (1)

Simon80 (874052) | more than 7 years ago | (#18125476)

Go to TH, and then go to that link URL again. They check the referrer to prevent people from deep linking to the printable page. That should be the first thing you try whenever similarly weird link breakage occurs.

Re:Printer Friendly (1)

hankwang (413283) | more than 7 years ago | (#18125774)

Go to TH, and then go to that link URL again. They check the referrer to prevent people from deep linking to the printable page.
Already tried that, but apparently THG doesn't like Opera. The link works in Firefox, though.

IntelliTXT too (3, Insightful)

Skadet (528657) | more than 7 years ago | (#18124848)

Yeah, between that and IntelliTXT, I pretty much gave up.

What if your hard drive [] decides to enter the Elysian Fields [] in this very moment? [] Sure, you could simply get a new hard drive [] to substitute for the defective [] one with a quick run to your favorite hardware store. And with last night's backup [] you might even reconstruct [] your installation quickly. But what if you don't have a backup? We have experienced [] the truth to be more like this: many users don't even have a backup, or it simply is too old and thus useless for recovering any useful files at all. In case of real hard drive damage [] , only a professional data recovery specialist can help you - say bye-bye [] to your vacation savings [] !
Anyone remember when Tom's Hardware was good?

Re:IntelliTXT too (2, Insightful)

operagost (62405) | more than 7 years ago | (#18125314)

Besides dedicating only about 10% of the page to actual content, the grammar is actually even worse than it used to be. Don't they have any native English-speaking editors?

Re:IntelliTXT too (0, Redundant)

mobby_6kl (668092) | more than 7 years ago | (#18125350)

>Anyone remember when Tom's Hardware was good?


Re:IntelliTXT too (1)

Mad Quacker (3327) | more than 7 years ago | (#18126088)

Anyone remember when Tom's Hardware was good?
Not actually I don't, I remember when they said 30 FPS is enough for everybody and professed it as the ultimate authoritative truth. I hope by now it is clear to everyone how false that is. Like claims about WMD's. I'm still waiting for a public retraction on both fronts.

Re:IntelliTXT too (-1)

Anonymous Coward | more than 7 years ago | (#18126218)

>Not actually I don't, I remember when they said 30 FPS is enough for everybody and professed it as the ultimate authoritative truth.

Well, it is (actually, about 24 fps seems to be enough, you don't find many people complaining about fps for movies, right?). The missing piece to the puzzle is that there's more to it than that. You need to simulate the motion blur accurately. I expect this is much more CPU intensive than simply upping the fps high enough that no motion blur is required to keep the brain happy.

That is, if we're talking from a quality standpoint. From the standpoint of "I don't care if it's ASCII Art, as long as it makes it easier to get frags" your best bet is probably to go with a text console where you can type things like Frag(Player1).

Re:IntelliTXT too (1)

Mad Quacker (3327) | more than 7 years ago | (#18126598)

Well, it is (actually, about 24 fps seems to be enough, you don't find many people complaining about fps for movies, right?). The missing piece to the puzzle is that there's more to it than that. You need to simulate the motion blur accurately. I expect this is much more CPU intensive than simply upping the fps high enough that no motion blur is required to keep the brain happy.
I guess I was wrong.. 24fps enough for a illusion of motion, not what emulates reality, motion blur or not. It's quite easy to see discrete frames in the movie theater. But lots of people think we found WMD too..

Re:IntelliTXT too (2, Informative)

PitaBred (632671) | more than 7 years ago | (#18126474)

* is blocked in my adblock list. Makes hundreds of sites more readable.

Re:Gotta love Tom's articles (0, Flamebait)

not5150 (732114) | more than 7 years ago | (#18124880)

Heaven forbid they actually try to make money to pay employees, office leases and equipment.

Re:Gotta love Tom's articles (1)

fossa (212602) | more than 7 years ago | (#18125084)

This should be obvious, but if they annoy the readers too much, they won't be making any money.

Re:Gotta love Tom's articles (1)

Evil Adrian (253301) | more than 7 years ago | (#18125194)

You're talking to the open source crowd, they don't believe in making money.

Re:Gotta love Tom's articles (0)

Anonymous Coward | more than 7 years ago | (#18126904)

What? You think Ontrack didn't pay them enough already or something?

Re:Gotta love Tom's articles (1)

fossa (212602) | more than 7 years ago | (#18124932)

I never understood the "next page" obsession that various websites have. I assume it's a way to fit more advertising in a given article, but why not, instead of splitting articles over multiple pages, simply insert more advertising on a single page? Are publishers afraid multiple ads will not load immediately? Surely loading an entire new page is worse than one more flash box? Do contracts require a given ad to have its own page? I'm curious.

Re:Gotta love Tom's articles (1)

gEvil (beta) (945888) | more than 7 years ago | (#18125250)

I assume it's a way to fit more advertising in a given article, but why not, instead of splitting articles over multiple pages, simply insert more advertising on a single page?

Let's see...10 ads per page spread out over 10 pages? Or 50 ad per page spread out over 2 pages? Both are very annoying, but if I can't even find the article text in a sea of ads, I'll never visit the site again. Then again, Tom's crossed that threshold for me a long time ago...

Re:Gotta love Tom's articles (1)

nschubach (922175) | more than 7 years ago | (#18126032)

I had a designer tell me once that people don't like to scroll. ("wtf!?") They want to read everything on one page. If they want to read further, they will click the link. I'm sure Ad revenue has a fair bit of play in it as well.

Re:Gotta love Tom's articles (1)

anagama (611277) | more than 7 years ago | (#18126236)

I wonder if there are any actual stats on this because I just don't believe it. Well, maybe I believe it but I certainly prefer to scroll. It requires no aiming of the pointer and clicking - just grab the mouse, have it inside the window I want to scroll (a big target), and then scroll. Scrolling is too easy to get such short shrift.

Re:Gotta love Tom's articles (1)

fossa (212602) | more than 7 years ago | (#18126254)

(This isn't directed at you, just poor design) Readers may not like to scroll, but they hate waiting for page loads even more. At least that's what Edward Tufte implied at a conference. Also see discussion at Tufte's website [] . Some interesting points raised. I suspect that the real issue is the page loading speed, rather than the action required to get there. Once loaded, scrolling is instantaneous. Paging could be, but would require different formats (e.g. PDF) or cleverer browsers (I thought I heard something about a Firefox plugin that could convert "next page" links into a single large page?).

Re:Gotta love Tom's articles (1)

Duncan3 (10537) | more than 7 years ago | (#18126258)

Hey, if advertisers are stupid enough to pay Google 10 times to show an ad to the same person, they deserve what they get...

Which is to have to sell stuff at such a high markup noone buys them. HA HA!

Generally I just smack a few of the Guild around (1)

Timesprout (579035) | more than 7 years ago | (#18124698)

And tell them to cause more damage next time or I will tell everyone they secretly admire Steve Ballmers commitment to developers.

Could have mentioned other options (2, Informative)

Bearhouse (1034238) | more than 7 years ago | (#18124728)

OK, this is for the very extreme (and rare) cases where the disk is physically very damaged. Most of the time, you'll find that available tools are enough. See [] , for example. Has worked for me, but 1. Copy the entire disk contents first. 'Low-level' disk-to-disk dup utilities (Seagate...) can work fine here. 2. Be prepared to wait. Of course, if your disk is on its way out, the intensive reading, (and writing, in the case of SpinRite) may accelerate its demise. Keep the disk at a constant, cool temperate, (stick it in a domestic freezer if you've no aircon).

Gibson the Hack (3, Insightful)

spun (1352) | more than 7 years ago | (#18124922)

SpinRite is a Steve Gibson product. Steve Gibson is a pompous blowhard with few real skills [] . There are plenty of other ways to do a low level copy of a disk.

Re:Gibson the Hack (1)

SEMW (967629) | more than 7 years ago | (#18125038)

The criticisms on the Wikipedia article you linked to were all regarding internet security. That says nothing whatsoever about how good or bad Spinrite is. I happen to write terrbile poetry; that doesn't say anything about how good any Mathematical papers I may produce would be.

Re:Gibson the Hack (1)

spun (1352) | more than 7 years ago | (#18125196)

True. But Spinrite follows the Gibson pattern: do something that everyone else is doing, but because of ego, do not pay attention to what anyone else is doing and reinvent the wheel over and over again. When people point out the stupid mistakes you make because you think everyone else in the world is inferior to you, attack them.

Spinrite isn't bad, per se. It's just not in any way revolutionary or important. There are many better tools out there for doing low level copies.

Re:Gibson the Hack (1)

Bearhouse (1034238) | more than 7 years ago | (#18125262)

I'm no Gibson fanboy, and have used - and mentioned - other tools (and others are referenced in the Wiki). Was just saying that I've used SpinRite, and it worked for me. If you've better tools to suggest, why not mention them, please?

Re:Gibson the Hack (1)

martin-k (99343) | more than 7 years ago | (#18125496)

ddrescue and a fridge. You'll be amazed how little data is typically damaged on a dead hard disk.

Be sure to use the ddrescue version that works with a logfile, so that you don't have to write down the blocks that you could rescue.

Re:Gibson the Hack (1)

spun (1352) | more than 7 years ago | (#18125558)

It's not so much that it doesn't work, it's that he is a huckster and tried to drum up business with FUD and pseudo-science. I'll copy and paste the criticism of spinrite here:

POSTED TO comp.dcom.xdsl] ken [or was it Steve Gibson -- do I detect a troll here?] wrote:

>What you don't know is that John Navas used to work for a hard disk >manufacturer twelve years ago ... and that he's had a serious personal >hatred for me (due to my SpinRite product) ever since. ...

Here are the facts:

As I recall my first encounter with Steve Gibson was when I was managing development for a principal disk technology manufacturer and he was promoting an earlier version of SpinRite. At that time I had about 15 years of experience in disk technology. My sincere efforts to help Steve correct some of the more serious errors in what he was saying proved to be a complete waste of time.

His subsequent "hard disks die!" campaign only compounded the problem. He was spreading hysteria then (for his own apparent gain), and he is doing it again now with Shields UP! The assertion that "hard disk die!" was based on a claim that magnetic patterns "weaken" over time, and that SpinRite could somehow "refresh" them.If this were true, then IDE drives, which cannot be "refreshed," would be dying all over the place, not to mention all the old mainframe drives that had already been running steadily for years. Furthermore, the embedded magnetic servo (used in virtually all reasonably current disk drives) can only be written at the factory.

If it "weakened" then the drive would fail permanently -- SpinRite could not possibly help. The fact that IDE disks have not been failing all over the place due to "weakening" and lack of "refreshing" by SpinRite is clear evidence that the claims were false. (Most problems with older MFM/RLL drives that SpinRite claimed to fix were the result of drives not being properly low-level formatted at working temperature on the actual controller in the end user's computer. This problem was easily solved by using the standard low-level format in the actual controller.

That SpinRite could also correct the problem meant nothing, since all it was doing was using the same controller.) Worse, Steve encouraged people to use SpinRite to "recover" areas that had been detected and marked as defective at the factory, a bad idea that leads to more failures in the long run, since end user controllers are not as sensitive as factory test equipment -- they are simply incapable of the kind of thorough testing done at the factory. Then of course SpinRite would be "needed" again to "fix" those failures, a self-fulfilling prophecy. As for the people that swear by SpinRite, there are lots of people that believe in astrology, but that doesn't make it any more valid.

I suggest that those with a technical bent visit the SpinRite website and see they can swallow such things as:

        * "prevents mass storage systems from crashing" (nothing can do that)
        * "sophisticated magnetodynamic physics models" (pseudo science)
        * "weakest possible magnetic signals" (not real)
        * "we doubt whether anyone but Steve and a handful of aliens would even know what all this is" (no argument there)
        * "Weak Bits" (no such thing)
        * "gradual evolution of the drive's storage surfaces through physical and magnetic stresses" (mumbo jumbo)
        * "SpinRite is actually able to lower the amplification of the drive's internal read-amplifier" (impossible, and after all this time Steve apparently still does not know that data is recorded on magnetic disks with flux reversals, not "amplitude")
        * "mass storage systems need periodic preventive maintenance" (nonsense)
        * "yeah, we know, Steve's a magician with his code" (how modest)

As for all the "exclusive" SpinRite features, many if not all of them are anything but exclusive; for example, testing disk surfaces with worst-case data patterns goes back many years before Steve ever thought of SpinRite. SpinRite is 80% hype, 10% dangerous, and 10% real substance. Likewise Shields UP! (See my assessment of Shields UP! and judge for yourself at .) -- Best regards, John Navas CABLE/DSL TIPS:

Re:Gibson the Hack (1)

gEvil (beta) (945888) | more than 7 years ago | (#18125294)

That may be so, but I gotta say that he did write a damn fine disk repair/recovery utility...

Re:Gibson the Hack (1)

operagost (62405) | more than 7 years ago | (#18125364)

Your argument is what we'd call "poisoning the well". Many have successfully recovered data using Spinrite, so however much of a "hack" or "blowhard" Steve Gibson is, he seems to have done well with Spinrite.

I'm trolling, ignore me. (1)

spun (1352) | more than 7 years ago | (#18125470)

Oh, I'm just trolling. Ignore me. It was mostly an excuse to make a "hack the gibson" joke. It was a dumb joke anyway.

Re:Could have mentioned other options (2, Interesting)

goarilla (908067) | more than 7 years ago | (#18125338)

what's wrong with popping in a livecd like sysreccd []
and to use dd to take an image of the disk or ghost (but iirc ghost uses dd) ?
i have been able to successfully recover 99% of a crashed, broken, badly partitioned hard drive that way numerous of times
offcorse i do not claim i have the expertise as ontrack but seeing as i've done this for quite
a few friends and since well not everybody can pay what they ask for their service, i can understand
why they get drives that have been subjected to a DIY recovery at first

But why do we need all these expensive consumer disk recovery tools, that often do not work correctly
i must agree on the issue that this article is mainly advertising but that is to be suspected
i mean the dude works in that company, he's kinda obligated to praise the so called 'superiority' of their own proprietary tools.

granted i don't have a clean room but the area in that so-called clean room doesn't seem so clean
and well the platters hanging on the top right on the other picture doesn't strike me as a good idea neither
that obviously wasn't a clean room and i would at least encourage the use of a static bag anyway.

Re:Could have mentioned other options (1)

GatorMan (70959) | more than 7 years ago | (#18125384)

SpinRite is not an alternative to professional data recovery, but simply one of the many steps you can take during the recovery process. SpinRite does not repair a seized motor assembly, failed electronics (circuit board or otherwise), damaged/failed read/write head assembly, firmware corruption, etc...these symptoms need to be diagnosed and repaired by an experienced recovery specialist. Many situations, 60% by Ontrack's figures, do not fall under the 'software coulda got it' category.

Re:Criticisms? (0)

Anonymous Coward | more than 7 years ago | (#18125408)

Why is there even a criticisms section?

OK, he's not always right and may be egotistical...

And that makes him different from other people how?

Linus Torvalds is constantly getting in disputes with kernel hackers and such. There's no "criticisms" section on his entry?

Re:Could have mentioned other options (1)

greg1104 (461138) | more than 7 years ago | (#18126754)

Spinrite was a sometimes useful utility in a few years following its earlier releases; I know I saved a drive or two with it back in the day back where it was the only useful tool around for home recovery work. We moved past that period quite some time ago. For many years now, hard drive electronics have corrected errors like bad sectors at a level well below where it's possible for Spinrite to operate at. Gibson and company should have withdrawn Spinrite from the market some time ago. Do not be fooled by the fact that it's still for sale into thinking that it still works on modern equipment. You should just run the drive manufacturer's disk utility instead, that will force a SMART scan that's far more useful than Spinrite.

Whether it's worth copying the drive to another one before trying recovery is very dependant on how much data is lost, and how much work it will take to setup for that copy. I've had drives where the act of shutting the system off and moving the bad unit was enough to fully kill it; the disc never spun back up again once it stopped. If you only have a small amount of data to get off, you may be better off just trying to do the recovery without powering off the system at all.

For recovery of Windows based systems from only partially damaged drives, the best affordable consumer-level tool I've found is iRecover [] . I've recovered gigabytes worth of data lost on lost drives with that tool; highly recommended if you've lost the filesystem, but the drive still spins and you can access it from your PC.

Questionable advice from Tom's (5, Interesting)

greg1104 (461138) | more than 7 years ago | (#18124816)

I have a concern with the recommendations given in the introduction:

We assume that all hard drives will be handled with care, so they should be installed in suitable drive bays. If you use multiple drives, we recommend removable drive frame solutions, which help reduce vibration transfer onto the computer chassis and even back to individual hard drives. Make sure that your system has sufficient ventilation, so high speed hard drives won't overheat.

I've found that the removable drive frames available for cheap consumer hardware to be total crap. The metal enclosure keeps heat close to the drive, and the tiny fans used don't move nearly as much air past the drive as when it's inside the case, being cooled by the airflow of the case fans. The drive temperature is therefore higher even under the best conditions. In addition, the smaller fans fill with gunk quickly and as a result wear out faster than larger ones, leading regularly to a drive trapped in an uncooled box.

I've used enclosures from Promise, Enermax, and several other companies whose products were so bad I tried to forget their names; all had fans that instantly became the least reliable part of the entire system once I installed the drive frame, and I wasn't happy with the drive's temperature from day one.

I don't think the person making this comment at Tom's ever keeps systems running long enough to realize the long-term issues that come with anything cheaper than server-grade drive enclosures for hard drives. I'd welcome suggestions for a better quality product in this category. It's a hard subject to cover, because by the time you've had several units setup for a year or two to gather useful data on how rugged they are, the product is obsolete; not something any review site I'm aware of is setup to cover.

And the alternative is? (1)

wsanders (114993) | more than 7 years ago | (#18125102)

A sun D1000 loaded with latest-generation 300GB disk drives? Not a bad solution, slow, and not the cheapest.

Apple X-serve RAID? Cheapest - does it work reliably with Linux or Solaris? Word in the street is that it does, but I have not seen a demo yet.

We're actually going with recycling our ancient D-1000s and A-1000s with no-name 300 GB SCSI drives. Pretty old school, but reliable.

Re:Questionable advice from Tom's (1)

onetruedabe (116148) | more than 7 years ago | (#18125374)

Stupid hint: space your disks at least one drive's width apart if possible.

It seems obvious, but if you have three internal 3-1/2" bays, put your disks in slots #1 and #3 so there's some ventilation between them.

Kinda like urinal etiquette...

-- :- Dabe

Re:Questionable advice from Tom's (0)

Anonymous Coward | more than 7 years ago | (#18126350)

Wrong. Airflow needs to be over the hot components on the drive electronics. Enterprise class RAID chassies require blocking unused drive bays to prevent air from missing the drives that are present. Adding empty space lowers the airflow where you need it - on the hot drive components.

If you want cooler drives, which you do, have dedicated fans or blowers and force the air over the drives.

Is there such a thing as... (1)

ALecs (118703) | more than 7 years ago | (#18125050)

RAID 11? Or, more to the point, how would I implement a mirror, but with 3 drives? Does linux 'md' do this? How about any controllers?

After all, we're supposed to replicate data 3 times, right?

Re:Is there such a thing as... (1)

operagost (62405) | more than 7 years ago | (#18125430)

You would set up the third disk as a hot spare. The mirror would rebuild onto it. Your hypothetical 3-disk mirror would be safer (because no rebuild time would be necessary), but it's pretty impractical. I would recommend investing in an additional disk and using RAID-6 (aka ADG).

Whatever you want, linux md RAID-1 can do it (1)

fnj (64210) | more than 7 years ago | (#18125648)

how would I implement a mirror, but with 3 drives? Does linux 'md' do this? How about any controllers?

Linux md RAID-1 allows you to replicate to n number of drives, PLUS set m more drives as spares that will be automatically substituted for failed drives without intervention. You can spread the drives among as many controllers as you want.

Of course you need off site backups too (fire, theft, lightning, human error).

Re:Is there such a thing as... (1)

multipartmixed (163409) | more than 7 years ago | (#18125674)

Solaris Volume Manager (aka ODS and SDS) does this out of the box. I wouldn't be surprised if other LVMs do too.

With SVM, create three stripes, create a mirror with one stripe, newfs it, when the newfs is complete, add a stripe to the mirror, (and then add another stripe to the mirror).

The stuff in the brackets is the only difference between creating RAID 1+0. Oh, and you don't want to use the GUI...

FWIW, my standard rollout these days is software-triple-mirrored hardware-RAID5 enclosures with an independant path to each enclosure. I have no idea what the hell you call that. I originally set out do to a typical three-mirrors-of-stripes, and then realized that I could just add my hotspares in as RAID 5 parity and pretend that I had pre-populated hot spares from a reliability point of view.

Re:Is there such a thing as... (0)

Anonymous Coward | more than 7 years ago | (#18126568)

Yep. Linux md definately does this. Just create a RAID1 and if you are using /etc/raidtab, just set it to have 3 devices.
I use this because lilo will not read a kernel from a RAID5 array, so I create /boot mirrored on 3 drives (RAID1) and / gets to be a RAID5. No special controller needed.

Re:Is there such a thing as... (0)

Anonymous Coward | more than 7 years ago | (#18126688)

Currently I'm running RAID1 with 4 disks for the lack of any better way of handling the extra disks in a 4-disk raid5 bootable system. Since I can't directly boot the raid5, the raid1 partition is used to boot the kernel. Since I have 4 disks and wanted all to be partitioned the same way, well, no sense in wasting the other partitions that really don't need to be part of a dual disk raid1...

Kroll Ontrack this and Kroll Ontrack that... (1)

singingjim (957822) | more than 7 years ago | (#18125068)

We've been Slashvertised! It's as good a reason as any why more options weren't offered up.

Backing up HDDs is very hard (2, Interesting)

AmiMoJo (196126) | more than 7 years ago | (#18125166)

With recent articles on HDDs not being very good for redundancy (because they often fail at the same time if they are from the same batch, or fail because of things like electrical spikes which affect all drives in an array) it is clear that HDDs are not an ideal backup medium. I use an external 2.5" HDD which is totally disconnected from the PC and everything else when not in use (to avoid power surges etc), but only for critical data as my machine has 1.2TB of HDD storage.

Optical discs are a joke - 4.3GB is just not enough. Larger formats exist but are relatively expensive. Tape is expensive per MB and slow, plus it isn't random access and not suited to anything but slow full backups. MO is too small and expensive.

It seems like the best bet is something like a Century Tower - basically a USB enclosure that can take up to 4/8 drives. Keep it totally disconnected when not in use, and use RAID 0 mirroring with drives from different manufacturers.

Re:Backing up HDDs is very hard (3, Informative)

operagost (62405) | more than 7 years ago | (#18125590)

Optical discs are a joke - 4.3GB is just not enough. Larger formats exist but are relatively expensive. Tape is expensive per MB and slow, plus it isn't random access and not suited to anything but slow full backups.
Your knowledge is out of date. For example, a SuperDLT 640 backs up at 32 MB/s with compression. Slower than a disk, but not "slow". Sequential access: well that's a given. Only suited for full backups? That's news to my company. Even daily incrementals and differentials are usually hundreds of megabytes or a few GB, which negates the small spool-up time of the tape. Besides, most modern tapes now store metadata on an internal chip so that an on-tape index does not need to be searched.

use RAID 0 mirroring
RAID 0 is striping. You probably mean RAID 10 or RAID 0+1.

raid data recovery (1)

ak_hepcat (468765) | more than 7 years ago | (#18125460)

Oooh, and this just happened to me a few weeks ago. well, not quite, but close enough.

I had an LVM container that sat on a RAID-1 volume go bad.

the lvm tools couldn't reconstruct the container, so I effectively 'lost' my partitions.

There wasn't any program I could find which would scan the raid volume for the data partitions,
so I ended up cobbling one together on my own, out of the sources in the ext2-tools distro.

And yes, I did get my data back, and no, i'm no longer using LVM containers.

Solution:RAID 50, 2 spares + RAID 50 backup + tape (0)

Anonymous Coward | more than 7 years ago | (#18125754)

Why don't people just run hot spares in their arrays? I lost a drive in my primary RAID 50 array and it re-built it from the hot spare in less than an hour. Now I'm down to "only" 1 hot spare left and I have plenty of time to replace the other one before I get worried.

Of course we also have 6-hour off-site snapshots to another RAID 50 and 3 month tape archives.

Keep in mind this is for an academic computer system, so we're pretty happy with the level of reliability.*

*Except that when some user creates 78,000 files in his home directory it causes rsnapshot to fail because the GNU cp command can't handle that many files in one directory...

Cheap Solution (2, Informative)

SwabTheDeck (1030520) | more than 7 years ago | (#18125834)

I'm a big fan of the hard drive->freezer method. It has been alleged that putting a broken hard drive into a freezer can sometimes make the data readable again for a short period of time.

Re:Cheap Solution (1)

Jjeff1 (636051) | more than 7 years ago | (#18126306)

It's true, but only for specific problems. We used to call it stiction [] at the shop I worked at. I don't think we really knew what we were doing, but if the drive didn't spin up, putting it in the freezer could fix it. It usually fixed it enough to spin up and get your data back, but that was good enough.

Re:Cheap Solution (1)

Intron (870560) | more than 7 years ago | (#18126458)

My wife's laptop drive (30 GB Travelstar) went bad and I did this. After trying everything else, I put it in the freezer for a couple of hours. It brought it back to life long enough to get most of the data off, then died for good.

backups (2)

hurfy (735314) | more than 7 years ago | (#18126022)

Besides having a backup not connected to system, i found simply having a spare disk to steal the circuit board off of to be a life saver :)

I miss the old bigfoot drives we had, everyone said they had problems with them but it was always (in our case) the board that died NOT the disk. I saved a couple of those by swapping in a board for a 1 hour recovery.

If you buy several HD for RAID or whatever buy one more and stick it on shelf for a rainy day. Along with a few utilities you can do 3/4's of what they do for $100 instead of $1000+

Lunch (3, Interesting)

Seraphim_72 (622457) | more than 7 years ago | (#18126372)

I attended a small conference where the Kroll VP of Data Recovery was speaking. He came in, his assistant set up his power point stuff, made sure the projector was right etc. He then gave a very interesting talk about what Kroll could pull off of a drive, despite what had been done to it. By way of example he showed a slide of a burnt and bent hard drive - that came out of the sky when the shuttle broke up. They recovered 99% of the data on that drive. He also mentioned that they do the data recovery for all of the spook organizations in D.C.

When we broke for lunch I got to sit at his table and we got to ask him all sorts of questions about their processes. He mentioned they have things they use that they have never patented because it would be too much of a leg up for both the competition and those that seek to destroy data. We tried to get him to tell us what we would have to do to a drive to make it unreadable. Mostly his answers to our "Surely this would make the data unreadable" queries were "You would think that would work wouldn't you?" Someone referenced his assistant who was sitting next to him and the VP said:

"Him? No, no, no. (laughs) He is not my assistant, in fact he doesn't work for me at all. He is a lawyer for the company and is here to make sure I don't say anything I am not supposed to." The assistant then gave us one of those 'I could eat you alive' lawyer smiles.

I walked out secure in the knowledge that short of melting the platters down the data can *always* be recovered.


Re:Lunch (1)

rthille (8526) | more than 7 years ago | (#18126570)

I've got those thermite packs against the drives in my server for a reason damn it!

Actually, I suppose if I was really paranoid I could use the welding torch in the garage to melt the drives down, but I don't think I'd get as much for them on eBay...

Truly astonishing...but so simple (2, Informative)

hrrY (954980) | more than 7 years ago | (#18126496)

As long as you know how the RAID config was setup(striping size), most disk recovery programs will do the job just fine. GetDataBack NTFS is functional and simple tool to use as long as you know how the disks were setup. Including RAID5...I've rebuilt 3 RAID5's and a shitload of 0's, 1's, and 01's. You should see the look on some of these people's faces after your done(with all 18+hrs of it...)The problem usually I find is that if you recovered the data then the customer is usually under the impression that you *fixed* the disk and they can keep on using it without replacing yeah, it's not a big deal it's just a question of how much time you want to spend and how much time you have to finish the job.
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