Re: [GENERAL] Log shipping in v8.4.7 - Mailing list pgsql-general

From Christoph Moench-Tegeder
Subject Re: [GENERAL] Log shipping in v8.4.7
Date
Msg-id 20170827192346.x2fg3pif2ip4bydo@squirrel.exwg.net
Whole thread Raw
In response to [GENERAL] Log shipping in v8.4.7  (Ron Johnson <ron.l.johnson@cox.net>)
List pgsql-general
## Ron Johnson (ron.l.johnson@cox.net):

> Everything I've read says that you should use "rsync -a".  Is there
> any reason why we can't/shouldn't use "rsync -az" so as to reduce
> transfer time?

On today's LANs, total archiving time is dominated by connection
startup time (how long does it take to transfer 16MB on a 10GbE link?
See...). That's even worse when using rsync via ssh transport without
ssh's connection multiplexing - key exchange and authentication
can easily take longer than the data transfer. Compression won't
save you much time, but sure won't break anything either (but
it will take some amount of CPU time).
On really slow links, your mileage may vary.

> Also, does that change require a full restart (difficult with
> production systems)?

Even in 8.4 archive_command is marked PGC_SIGHUP, so a reload
will be sufficient. The sample configuration and perhaps pg_settings
(can't remember how informative that was back then) should
tell you the same.

Regards,
Christoph

--
Spare Space.


pgsql-general by date:

Previous
From: Ron Johnson
Date:
Subject: [GENERAL] Log shipping in v8.4.7
Next
From: Ron Johnson
Date:
Subject: Re: [GENERAL] Log shipping in v8.4.7