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Comment by maerF0x0 | Hacker News Reader

As many have pointed out: There are many applications where power cycling is extremely rare and also not a big deal.

1. Laptops have a built in UPS incase they're unplugged 2. Servers should have UPS incase they're unplugged or small outtages 3. Desktop drives shouldnt be trusted as the only copy. Though I imagine the data corruption would propagate to backups?

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Servers can go down more than you think. Rackspace had an entire wing of their Texas data center go down hard 3 times within a couple months a few years back. I know because PortableApps.com's dedicated box was in that wing. It was an issue with the equipment that switches form external power to battery to generator power. And there was no secondary backup to that, so it would go down and take the whole wing all at once. This would corrupt our Drupal database and it would take about 8 hours to rebuild. So, having a reliable SSD with power loss prevention could be a lot more relevant than you expect.

Unless the server UPS is inside the chassis, disk corruption on power loss seems like a very high risk. Datacenter-wide UPSes can fail (at one of XO's DCs, we had power loss 3 times in 2 months). People can accidentally unplug stuff.

Laptops are vulnerable to this problem, if you don't know about it.

On my notebook I've lost a partition with Crucial M4. OS hanged, I did a hard reset and after reboot discovered data loss.

I got an Intel SSD (G1 80GB) in my laptop to do OS development (drivers), which incidentally is a use case that requires lots of hard resets. Never had any problems with it, and it's been through dozens if not hundreds of hard reset cycles. In fact I got the SSD specifically because I didn't want to be spinning up/down a disk that much, and laptops tend not to have reset buttons (they really need one, IMHO.)

Those tend to be very safe hard resets from a drive perspective. First of all, you're not losing power, so even though there's a reset, the drive firmware maintained power. Secondly, I'm guessing you see far more hard locks and manual resets than random, sudden reboots - and if that's the case, then the drive firmware probably didn't even notice. By the time you press reset, an eternity has passed and any ongoing activities have long finished.

I can imagine a software-fault causing drive-level problems if the drive has a large cache and a broken fsync, or if the bios does some kind of unsafe hard drive reset very quickly after starting.

In any case, it's probably more likely to be file-system level reliability you'd need in the face of driver instability.

For me, the scariest/most interesting part was that some SSDs had problems with the tests in which power WASN'T interrupted.

> For me, the scariest/most interesting part was that some SSDs had problems with the tests in which power WASN'T interrupted.

OCZ drives had that problem. That's not a surprise.

There's a reason why Intel and Samsung drives consistently average 4.5 stars on Newegg, while OCZ drives consistently average 3-stars.

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