Re: Feedback about hybrid SAN snap and rsync'd approach for large systemcloning

On Tue, 2022-04-12 at 18:07 -0500, Jerry Sievers wrote:
> Suppose we have a DB cluster with an additional tablespace and we are
> able to make an atomic SAN snapshot of *only* the main cluster
> volume...
>
> The additional tablespace contains only UNLOGGED relations.
>
> We cannot snap that volume so we use rsync as follows...
>
> 1. pg_start_backup('foo');
> make SAN snapshot
> rsync the add'l tablespace
> pg_stop_backup()
>
> Now provision a new cluster around the snapshot and rsync'd volume,
> rejigger the pg_tblspc link if necessary... and start it up maybe or
> not having it remain as a streaming replica.
>
> It's been my experience that possibly bulky data in the additional
> tablespace does *not* need be rsync'd if we capture only the *_init
> files.
>
> Id' be curious to here feedback re the sanity of this approach.

I thought that an unlogged table is rendered empty by recovery,
but perhaps I misunderstood what you are doing.

Yours,
Laurenz Albe