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Mac geek stuff

sillypixie (696077) writes | more than 7 years ago

User Journal 12

Hope this isn't too stupid a question:

I've run an rsync backup of my Mac to an external drive, and now I'm trying to prove to myself that my backup is capable of being externally booted in the case of disaster.

I reboot holding down the option key, and I select my external drive as the boot drive -- then the machine comes up and looks identical, regardless of which drive I boot from.

Hope this isn't too stupid a question:

I've run an rsync backup of my Mac to an external drive, and now I'm trying to prove to myself that my backup is capable of being externally booted in the case of disaster.

I reboot holding down the option key, and I select my external drive as the boot drive -- then the machine comes up and looks identical, regardless of which drive I boot from.

How do I know that it worked? df shows that both disks are mounted, but I don't see my external drive mounted as root -- isn't that bad? /etc/fstab is empty. All the files in /var/log look similar no matter what boot disk is specified, I don't see any kind of error. I don't know how exactly the OS finds the bootable partition that I ran the "bless" command on -- and what happens if I put multiple backups on the drive and therefore there are multiple "CoreServices" directories blessed?

I'm vewy confused... I need to get my OSX book back from my dogwalker dammit...

If you happen to have been here done that and can point me in the right direction, I would appreciate it :)

Pix

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I punted (1)

peacefinder (469349) | more than 7 years ago | (#19590859)

I figured I didn't need to work that hard, so I bought SuperDuper. [shirt-pocket.com] It's not very flexible, but it gets everything. (There was a comparison of Mac backup software about a year ago, and almost everything else missed at least one subtle aspect of the filesystem, such as ACLs.)

Re:I punted (1)

sillypixie (696077) | more than 7 years ago | (#19594559)

See you're smart. But I'm still in serious pain over how much I've spent -- plus I have to know how the voodoo works now. I can't just accept the apple it-just-works magic in this case, not when I know there is a UNIX process somewhere in the background. It's different enough to require my attention :)

The rsync backup was painless too, I was quite impressed. No incrementals though. I suppose I could actually set up Amanda too, now that I think of it...

Jeez I'm waxing nostalgic over system administration of my own home network. Whoda thunk...

*grin*

Pixie

Re:I punted (1)

Nevyn (5505) | more than 7 years ago | (#19595447)

There are a couple of ways to do incrementals with rsync, I just hacked a "cp -al" in after rsync finishes (rsync copies to temp. files and does a rename() ... so this works). I've also seen people use some scripts (rdiff-backup, I think) that stores deltas between the old and new, as rsync does the backup (although this means you need all previous versions to go back to a specific version). I've no idea about OS-X though :).

Here's the article (1)

peacefinder (469349) | more than 7 years ago | (#19594645)

FYI. [plasticsfuture.org]

A low-tech workaround (1)

m50d (797211) | more than 7 years ago | (#19591677)

How about just disconnecting the internal drive to test it?

Re:A low-tech workaround (1)

sillypixie (696077) | more than 7 years ago | (#19593989)

I'm not sure how to open up my lovely new MacBook to get to the disk :)

Hm, I still have my old G4 powerbook - seems to me the disk is more accessible there -- perhaps I'll rsync that drive and then disconnect the internal drive. I'm giving that machine to my sister, and want to have it backed up anyways.

Excellent... :)

Re:A low-tech workaround (1)

SamTheButcher (574069) | more than 7 years ago | (#19608783)

I'm not sure how to open up my lovely new MacBook to get to the disk :)

Take out the battery and on the long end of the internal space there should be a few screws. Undo them and take out the L bracket and then pull out the drive.

Just about the easiest internal-drive-access in any notebook I've ever worked on. Definitely easiest access in any Apple notebook.

http://manuals.info.apple.com/en/MacBook_13inch_Ha rdDrive_DIY.pdf [apple.com]

Re:A low-tech workaround (1)

sillypixie (696077) | more than 7 years ago | (#19613281)

Rock n' Roll!!!!

Wow, this is definitely a case where it pays to RTFM. Or at least it pays to know people who RTFM. Thanks for being my FM-buddy, Sam!

Pix

Re:A low-tech workaround (1)

SamTheButcher (574069) | more than 7 years ago | (#19635549)

Don't mention it. Happy to share what I know. :)

So...just hang around Multiply more, and we'll call it even. :D

You're way ahead of me. (1)

sulli (195030) | more than 7 years ago | (#19596013)

How did you set up the backup? I should really do this. Backing up to DVDs sux.

Re:You're way ahead of me. (1)

sillypixie (696077) | more than 7 years ago | (#19596279)

I started at this site:

http://www.egg-tech.com/mac_backup/#advanced [egg-tech.com]

The backup script works like a charm, as long as you have an HFS-formatted partition to push it to - and over USB 2.0 the speed was really good. The only thing that needed to be tweaked was the actual mount-point of the external volume in question (this gets changed in 2 places).

It's just the booting-from-your-backup part where I became confused. all the partition information that I backed up would obviously relate to the internal disk, so it makes sense that even if I boot from the external drive, the partition map is going to try to mount the internal partitions. Yet there are no instructions on how to change what maps to root, etc. How you could get it to boot completely from the external drive without altering the backed up partition map?

I'll get to the bottom of it yet... and I'll let you know when I do.

Re:You're way ahead of me. (1)

sulli (195030) | more than 7 years ago | (#19610929)

I'll buy that just for the Doveryai no proveryai [wikipedia.org] reference! Thanks for the tip.
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