Re: [GENERAL] Backup

Magnus Hagander wrote:
> On Thu, Jan 31, 2008 at 03:34:05PM +0100, Martijn van Oosterhout wrote:
>
>> On Thu, Jan 31, 2008 at 01:28:48PM +0000, Simon Riggs wrote:
>>
>>> That sentence has no place in any discussion about "backup" because the
>>> risk is not just a few transactions, it is a corrupt and inconsistent
>>> database from which both old and new data would be inaccessible.
>>>
>> Hmm? I thought the whole point of a filesystem snapshot was that it's
>> the same as if the system crashed. And I was fairly sure we could
>> recover from that...
>>
>
> That was my assumption as well. *Assuming* that the filesystem snapshot is
> consistent. There are a bunch of solutions that don't do consistent
> snapshots between different partitions, so if your WAL or one tablespace is
> on a different partition, you'll get corruption anyway... (seen this in
> Big Commercial Database, so that's not a pg problem)
>
Agreed.  That's why I made it a point to mention that all of your
tablespaces should be on the same file system...  In hindsight, I should
have also stated that your WAL logs should be on the same file system as
well...

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Chander Ganesan
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