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

On Thu, Sep 1, 2016 at 8:48 PM, Patrick B <patrickbakerbr(at)gmail(dot)com> wrote:
> Hi guys,
>
> I'll be performing a migration on my production master database server,
> which is running PostgreSQL 9.2 atm, from SATA disks to SSD disks.
> I've got some questions about it, and it would be nice if u guys could share
> your experiences/thoughts:
>
> SCENARIO:
>
> I currently have one MASTER and two Streaming Replication Slaves servers...
>
>> master01
>> slave01 (Streaming replication + wal_files)
>> slave02 (Streaming replication + wal_files)
>
>
> ...Postgres is mounted on: /var/lib/pgsql/... The SSD disks will be
> installed only on my Master server, because my main problem is Writes and
> not reads.
>
> The new SSD volume will be mounted on /var/lib/pgsql2/
>
>
> The slave02 server will loose the streaming replication connection to the
> master, once slave01 becomes the new master a new timeline will be settled?
> Will slave02 be able to connect to the slave01 server for streaming
> replication?
>
>
>
>
> MIGRATION OPTIONS:
>
> Migration Option 1: I know this option will work
>
> Mount the new volume /var/lib/pgsql2/ on the master01 server
> Turn slave01 into a master server
> once I can confirm everything is working fine, I can go to step 4
> Stop postgres on the master01, start copying the DB using pg_basebackup from
> slave02 to master01 (Will have to edit postgres to use /var/lib/pgsql2/
> instead /var/lib/pgsql - Is that possible? Or I'd have to create a symbolic
> link?)
> Start postgres on master01 server and check if all goes well as streaming
> replication server (Will test it for days)
> Turn master01 into a master server and I'll have to re-copy the DB into
> slave01 to make it a streaming replication server again
>
>
> Migration Option 2: I don't know if this is possible - IS THIS POSSIBLE????
>
> Mount the new volume /var/lib/pgsql2/ on the master01 server
> Stop postgres on the server (I won't stop postgres on the slave so the users
> will be able to use the server as read-only)
> Copy the data from /var/lib/pgsql/ to /var/lib/pgsql2/
> Configure postgres to start using the new volume(/var/lib/pgsql2/)
>
>
> What do you guys think? Is option possible? if so it would be much easier :)
> Thanks!

Why not just subscribe to another cluster on the master, then sub the
slaves to that, then switchover to the new cluster on the master?

--
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