Re: Synchronization Master -> Slave (on slow connetion)

On Thu, Jul 19, 2012 at 4:27 PM, Sergey Konoplev
<sergey(dot)konoplev(at)postgresql-consulting(dot)com> wrote:
> On Thu, Jul 19, 2012 at 3:45 PM, Edson Richter <edsonrichter(at)hotmail(dot)com> wrote:
>> The rsync above can be optimized? Both servers are CentOS 5 with OpenVPN
>
> Yes, it can be optimized. You can turn compression on by specifying
> -z. The compression level 1 is the one that performs best for my
> needs. You can find out yours best by experimenting.
>
> rsync -av --delete -z --progress --compress-level=1 \
> --exclude pg_xlog --exclude *.conf --exclude postgresql.pid \
> /db/data db2:/db/
>
> But it is not the end. The replication's stream is not compressed
> itself and because of the nature of xlog it is quite bloat (if it can
> be said so). If you have a problem with the bandwidth it can be a
> reason of replication lagging and breaking.
>
> I usually start the following sniplet via screen utility on a master
> db. It will forward the localhost:5432 on the master db to the
> localhost:2345 on the replica.
>
> while [ ! -f /tmp/stop ]; do
> ssh -C -o ExitOnForwardFailure=yes -R 2345:localhost:5432 replica_address \
> "while nc -zv localhost 2345; do sleep 5; done";
> sleep 5;
> done
>
> The stream will be forwarded then. Direct your replica to
> localhost:2345 in the recovery.conf file.

Sorry, here I meant "the stream will be compressed then". See the -C
flag of the ssh utility.

>
> --
> Sergey Konoplev
>
> a database architect, software developer at PostgreSQL-Consulting.com
> http://www.postgresql-consulting.com
>
> Jabber: gray(dot)ru(at)gmail(dot)com Skype: gray-hemp Phone: +79160686204

--
Sergey Konoplev

a database architect, software developer at PostgreSQL-Consulting.com
http://www.postgresql-consulting.com

Jabber: gray(dot)ru(at)gmail(dot)com Skype: gray-hemp Phone: +79160686204