Re: EXTERNAL: Re: Netapp SnapCenter

On Thu, Jun 25, 2020 at 5:23 PM Paul Förster <paul(dot)foerster(at)gmail(dot)com>
wrote:

> Hi Ken,
>
> > On 25. Jun, 2020, at 17:15, Wolff, Ken L <ken(dot)l(dot)wolff(at)lmco(dot)com> wrote:
> > There's actually a lot of good stuff in that document about Postgres in
> general. I'd be curious to hear what everyone thinks, though, and
> specifically about what NetApp recommends in Section 3.3 about putting data
> and WAL on separate volumes, which I believe contradicts what's been
> discussed in this email thread.
>
> yes, I've read the part about different volumes and I must say, I don't
> agree because I think it violates atomicity.
>

I believe NetApp does atomic snapshots across multiple volumes, if you have
them in the same consistency group. (If you don't then you're definitely in
for a world of pain if you ever have to restore)

Snapshotting multiple volumes in a consistency group will set up a write
fence across them, then snapshot, and AIUI guarantees correct write
ordering.

--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/>
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>