On 2/21/18 7:01 PM, Tom Lane wrote:
Ron Johnson <ron.l.johnson@xxxxxxx> writes:
Apparently, initdb assumes that data/ is one big mount point. However, we
have four mount points:
/var/lib/pgsql/9.6/data/backup
/var/lib/pgsql/9.6/data/base
/var/lib/pgsql/9.6/data/pg_log
/var/lib/pgsql/9.6/data/pg_xlog
Don't do that.
Agreed.
There's no reason for backup storage to be under the data directory (and
lots of good reasons for it not to be). Just put it somewhere else.
Yes -- in this configuration your backups would be backed up with every
backup. It's pretty obvious where that would go.
The supported way to put pg_xlog on a separate volume is to put that
mount point somewhere else, and make $PGDATA/pg_xlog be a symlink to
it. IIRC, there's an initdb option to help with that, though you can
also make it so manually after initdb.
initdb supports linking pg_xlog/pg_wal with the --xlogdir/--waldir option.
For pg_log, just put it somewhere else and set the appropriate
configuration option to say where to write the postmaster log files.
Or you could use a symlink, like the solution for pg_xlog, but
I don't see any advantage there.
Symlinking pg_log is not ideal because the logs end up in the backup.
It gets pretty weird when those logs get restored to a standby and
somebody starts reading them.
I don't see any point in making base/ be its own mount point. Once
you get rid of those other subdirectories there's not going to be
enough "global" storage left to justify its own volume.
Agreed.
--
-David
david@xxxxxxxxxxxxx
