Constant rebooting after power loss
florian at wagner-flo.net
Sat Apr 2 20:18:46 UTC 2011
> I am unaware of *ANY* mainstream hard drive or SSD made in the
> last 10 years which ignores the disk flush command. In previous
> decades HD vendors played games with caching all the time but there
> are fewer HD vendors now and they all compete heavily with each
> other... they don't play those games any more for fear of losing
> their reputation. There is very little vendor loyalty in the hard
> drive business.
> When it comes to SSDs there are all sorts of fringe vendors, and I
> certainly would not trust any of those, but if you stick to
> well known vendors like Intel or OCZ it will work. Look for who's
> chipsets are under the hood more than for whos name is slapped
> onto the SSD and get as close to the source as you can.
As far as my knowledges goes all mainstream non-enterprise SSD do not
obey the cache flush command at all. The question for a recommended SSD
for ZIL-use regularly comes up on the zfs-discuss mailing list and the
general consensus seems that no non-enterprise SSD can really be
recommended because of this issue.
The only publicly available SSDs which do not exhibit this are those
with a Sandforce enterprise controller (SF-1500 if my memory serves me
correctly) and a capacitor (OCZ sells such models) and the Intel X25-E
with it's write cache turned off (also resulting in horrible write
performance all around).
I've had the chance to verify this with a Corsair Force SSD with the
SF-1200 controller. It consistently "lost" about 1,2 to 1,5 MB of data
which it claimed to have committed to disk.
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