News for hackers. Stuff that matters.

A comment on ST3000DM001. Parent comment

Re:ST3000DM001 by daneel_w on Monday June 07, 2021 @06:31AM (#27420965)
Do drives in this type of stationary assembly (i.e. a server rack or a stationary PC) ever trigger their vibration protection? Barring of course during a bit of bumping in the server rack. I mean, these drives are not sitting in laptops. I have a hard time thinking the lack of this feature bears any weight on the huge failure rates Backblaze and discrete customers saw, though I'd accept the argument if there was a 2.5" laptop model of that drive seeing the same failure rate.
[ Parent | on HN ]
Re:ST3000DM001 by doikor on Monday June 07, 2021 @08:48AM (#27421921)
As I understand it another driver in the same rack doing work is enough to effect the performance of the other drivers in the rack. This is why you use fancy expensive "enterprise grade" drives as they can cope better with it.

https://www.dtc.umn.edu/publications/reports/2005_08.pdf

> In the presence of an external vibration caused by adjacent disk drive seek operations the bandwidth performance of a consumer-grade disk drive “feeling” these vibrations will decrease about 10%-15% when reading data and about 25%-40% when writing data

Don't really know if this is enough to actually cause damage if the disk does not have the hardware to detect this vibration.

[ Parent | on HN ]
Re:ST3000DM001 by fuckyouriotshit on Monday June 07, 2021 @10:08AM (#27422795)
There's also this great example of Brendan Gregg screaming at hard disks to demonstrate exactly that sort of latency spike: https://www.youtube.com/watch?v=tDacjrSCeq4

I don't know if the latency spike is caused by sensors detecting the extra vibrations and delaying a read or seek operation or if its just vibrations causing minor read-head errors which either require a 2nd pass (that isn't reported through to the OS via SMART) or some sort of extra processing to pull the correct signal out of the raised noisefloor.

Edit: person shouting at the disks is Brendan Gregg, not Bryan Cantrill.

[ Parent | on HN ]
Re:ST3000DM001 by loeg on Monday June 07, 2021 @11:04AM (#27423407)
Apparently, yeah. Here's the classic video on the topic: https://www.youtube.com/watch?v=tDacjrSCeq4
[ Parent | on HN ]