Re: Install Postgres on a SAN volume?

Greg Smith wrote:
> On Tue, 9 Sep 2008, Magnus Hagander wrote:
>
>> As long as your SAN guarantees an atomic snapshot of all your data
>> (which every SAN I've ever heard of guarantees if you're on a single
>> volume - entry level SANs often don't have the functionality to do
>> multi-volume atomic snapshots, though), you don't need to set up PITR
>> for simple backups
>
> It's all those ifs in there that leave me still recommending it. It's
> certainly possible to get a consistant snapshot with the right hardware
> and setup. What concerns me about recommending that without a long list
> of caveats is the kinds of corruption you'd get if all those conditions
> aren't perfect will of course not ever happen during testing. Murphy
> says that it will happen only when you find yourself really needing that
> snapshot to work one day.

Well, I agree one should be careful, but I don't see the risk if you
just change all those ifs into a single one, which is "if all your data
*and* WAL is on the same SAN LUN".

(heck, you don't need hardware to do it, you can do software snapshot
just fine - as long as you keep all your stuff on the same mountpoint
there as well)

//Magnus