Re: Upgrading using streaming replication

On Fri, Mar 11, 2011 at 12:58, Damien Churchill <damoxc(at)gmail(dot)com> wrote:
> Hi there,
>
> I have done quite a bit of searching but have been unable to find any
> way to do this. I am quite keen to use PostgreSQL 9.0's streaming
> replication to create a master/slave write/read setup. However I am
> unsure of an upgrade procedure whilst using streaming replication that
> doesn't yield any downtime (including being able to write). From what
> I have read the WAL won't be compatible between 9.0 and 9.1 so it
> won't be possible to take the slave off-line and upgrade it, promote
> it to master and then upgrade the old master.

That's correct, you can'd do that.

> So I was wondering if anyone knows of a method that allows you to do
> this. Sorry if this is an often asked question and I just haven't been
> able to find the answer.

Using SR, the method will be to upgrade the master and then rebuild
the slave off that one. You can upgrade with pg_upgrade, which will
shorten your downtime, but there will be downtime.

For a downtime-less upgrade, you will need to look at one of the
"userspace replication solutions", like slony, bucardo, londiste etc.

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 Magnus Hagander
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