On 08/27/2017 02:23 PM, Christoph Moench-Tegeder wrote:
> ## 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...).
And if we've only got a WAN link from one DC to another 360 miles away?
> 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.
Thanks
