"Simon Riggs" <simon@2ndquadrant.com> writes:
> On Fri, 2007-06-22 at 13:12 -0400, Tom Lane wrote:
>> If you saw a problem I'd be inclined to question whether
>> there is some upstream component (OS or disk controller) that's
>> reordering writes.
> Given thats exactly what they do, constantly, I don't think its safe to
> say that it works since we cannot verify whether that has happened or
> not.
If he's trying to snapshot at a level of hardware that's behind a
write-caching disk controller, I agree that that's untrustworthy.
If not, ie if he's snapshotting the actual durable state of the storage
system, then any problems in the snapshot indicate a problem with the
database's ability to recover from a crash. So I don't think you should
tell him to not worry.
regards, tom lane
