Announcing: Slashdot Deals - Explore geek apps, games, gadgets and more. (what is this?)

Thank you!

We are sorry to see you leave - Beta is different and we value the time you took to try it out. Before you decide to go, please take a look at some value-adds for Beta and learn more about it. Thank you for reading Slashdot, and for making the site better!



When Does Powering Down Servers Make Sense?

VdG Re:PSU failures (301 comments)

I don't have numbers, but I have witnessed it.
The worst PSU case was with some IBM SP2 systems. These have multiple redundant power supplies. However, a design/manufacturing fault in some early parts meant that they were prone to failure on power-up and when they failed they'd trigger a failure in their bretheren. I encountered this the first time when we had a rack powered off for hardware maintenance, so the good news was we already had a scheduled outage. However, what with getting replacement parts the outage had to be extended by a couple of hours which wasn't popular with our users.

I've also seen PSUs fail on normal tower servers when they're powered on. A case which comes to mind was, again, a server powered off for hardware maintenance. One PSU failed at power-on but fortunately this time the redundant PSU was OK.

I've seen a couple of other types of hardware problems. The most common was with disk drives. Some older SCSi disks sufferred from stiction if left powered down for a prolonged period, (over an hour, say). Sometimes you could revive them with a bit of physical intervention; somteimes not. The worst case was when we had our entire machine room powered off for upgrades to the power supply. When we came to restart two servers wouldn't reboot because their boot disks wouldn't spin up, and half a dozen or so external disks failed. (Mostly these were mirrored, so it wasn't the end of the world, and the servers weren't critical.)

Several years ago we had a weird problem with a server, which took a while to identify. We got a lot of weird, intermittent I/O and memory errors, (iirc). Never actually brought the server down but they caused some application glitches and we couldn't find the cause. Eventually, one of the engineers worked out that a connector to one of the boards hadn't been seated correctly. Every time the server was shutdown, the pins would cool down and contract; when they heated up again they expanded and loosened the connector slightly, leading to the errors.

There may be something to be said for powering off idle equipment, but if so I think it's particularly important to have some redundancy built in.

more than 6 years ago

Police Lose National High-Tech Crime Unit Website

VdG What's the big deal? (93 comments)

Since it's my taxes that pay for it, I'm quite happy to see the registration lapse. This is a bit of a non-story and wouldn't be an issue if other people kept their links up-to-date.

more than 6 years ago

Photographers Face Ejection Over Lenses

VdG Re:America's really getting stupid (743 comments)

It's not just the US: there have been reports of photographers here in the UK getting hassled by people - including the police - for taking pictures in public places.

I think it's because a lot of people have bought into the security theatre, including police officers who should know better. Govt says so-and-so has all this dangerous information in his home, including photos of potential targets and eventually everyone starts thinking that photos are in some way dangerous.

With the number of cameras around it is a bit ridiculous. CCTVs in nearly every town centre; digital cameras in everybody's pockets; Google's lovely camera cars. Some enthusiast with an SLR really isn't a threat: someone who wanted pictures for nefarious purposes could get them quite simply with no-one the wiser.

more than 6 years ago

Warning Future Generations About Nuclear Waste

VdG Re:Orr we could (616 comments)

I agree that it seems the best way of getting rid of it. It'll even be recycled eventually. The biggest stumblinng block for that at the moment is international treaties restricting disposal of hazardous waste at sea.

more than 6 years ago


VdG hasn't submitted any stories.


VdG has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?