Thanks for your replies.
1) We use streaming replication, and due to hardware limitation, we cannot add more drives to the existing host. That is why we thought by breaking the existing streaming replication (from a->b), instead of currently identical standby (b), we can introduce twice larger host, then start the replication to the newly larger host, and when it is caught up, break it again. Then break rep again, make modification to 'a" host, making it larger, then replicate b->a. After it is caught up, break the rep again, switch master->standby (if necessary).
2) I am not sure about the time, but it is understood it is required 2 full replication cycles, and might be up to 2 weeks with no standby situation
3) Yes, we will clean up whatever we can to buy us time
4) by pg_basebackup and restore
As of now, we are thinking about possibly other solutions, as of splitting existing 37 databases on the cluster into 2 hosts with their own standbys. This solution requires breaking up existing replication as well. Can you please point me to some document which lists all steps describing breaking up the existing replication properly? we are using 9.6 postgres
Thank you!
From: Adrian Klaver <adrian.klaver@aklaver.com>
Sent: Thursday, August 1, 2019 7:28 AM
To: Julie Nishimura <juliezain@hotmail.com>; pgsql-general@lists.postgresql.org <pgsql-general@lists.postgresql.org>; pgsql-general <pgsql-general@postgresql.org>
Subject: Re: adding more space to the existing server
On 7/31/19 3:21 PM, Julie Nishimura wrote:
> Hello postgres folks,
>
> We're tossing around the idea of upgrading a replicated postgres cluster
> (37 dbs) by breaking the replication, adding different size (larger)
> data disks to the hot-spare, then turning replication back on, letting
> it fully populate, then breaking replication, making the standby the
> primary, upgrade the disks on the other system, bring it back up,
> replicate backwards until fully replicated then failing-back to the
> original primary. Is this feasible?
To make a determination more information would be helpful:
1) What is the method of replication?
2) What is the expected downtime for the disk upgrades?
3) Dependent on 1). Is there sufficient storage to hold the data until
it can be replicated back?
4) How is the data on the existing disks going to get to the new disks?
>
> Our current size is 22 tb, and it is 97% full
> (PostgreSQL 9.6.2 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
> 5.3.1-14ubuntu2) 5.3.1 20160413, 64-bit)
>
>
> Thank you for your suggestions
--
Adrian Klaver
adrian.klaver@aklaver.com
