Odd file system corruption in ZFS pool

[Bob Friesenhahn]

On Thu, 26 Apr 2012, Andrew Reilly wrote:

> On Wed, Apr 25, 2012 at 08:58:41AM -0500, Bob Friesenhahn wrote:
>> With properly implemented hardware (i.e. drives which obey the cache
>> flush request) it should not be possible to corrupt zfs due to power
>> failure.
>
> Does that comment apply to enerprise-class SATA drives?  I was
> under the impression that all SATA drives lied about cache flush
> status.  Hence the notion that I need to get myself a UPS.

A blanket statement like that (about SATA drives) would not be very 
accurate.

UPSs are quite valuable in that they help the system avoid marginal 
operating conditions.

If power is lost while a drive is currently writing, perhaps it will 
move the head to the wrong position and write to the wrong place on 
the disk, or perhaps the data it does write will be junk.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/