Re: 2.5TB Migration from SATA to SSD disks - PostgreSQL 9.2

Hi guys,

You can actually reduce the time more by pre-syncing to the new location.

something like:

rsync -va /var/lib/pgsql/ /var/lib/pgsql2/

service postgres stop

rsync -va /var/lib/pgsql/ /var/lib/pgsql2/

The second rsync will only copy the deltas from the first, it still has to
> go in and determine what needs to be copied/what changed but the bulk of it
> can be prepared/migrated before the actual downtime window.

Thanks a lot @David.

I tested the above and it worked... Here is what I did:

1 - Create /var/lib/pgsql2 directory
mkdir /var/lib/pgsql2

2 - Set permissions:
chown -R postgres:postgres /var/lib/pgsql2

3 - Change postgresql.conf:
data_directory = '/var/lib/pgsql2/9.2/data/'

4 - RSYNC:
rsync -va /var/lib/pgsql/ /var/lib/pgsql2/

5 - Stop postgres
/etc/init.d/postgresql-9.2 stop

5 - Re-run RSYNC to incremental copy:
rsync -va /var/lib/pgsql/ /var/lib/pgsql2/

6 - Change /etc/init.d/postgresql-9.2:

*OLD:*
PGDATA=/var/lib/pgsql/9.2/data
PGLOG=/var/lib/pgsql/9.2/pgstartup.log
PGUPLOG=/var/lib/pgsql/$PGMAJORVERSION/pgupgrade.log

*NEW:*
PGDATA=/var/lib/pgsql2/9.2/data
PGLOG=/var/lib/pgsql2/9.2/pgstartup.log
PGUPLOG=/var/lib/pgsql2/$PGMAJORVERSION/pgupgrade.log

7 - Start postgres
/etc/init.d/postgresql-9.2 start

and it worked perfectly fine... :)

That's great news! My only concern is about the "*RSYNC*" - Hope that
doesn't take long!!!

This all steps must be performed by me on the next few days/weeks - I'll
keep you guys updated... Keen to see the new DB running in a SSD
environment :)