On Mon, Jan 06, 2014 at 08:17:37AM -0800, Adrian Klaver wrote: > On 01/06/2014 07:35 AM, Martijn van Oosterhout wrote: > >On Mon, Jan 06, 2014 at 07:16:25AM -0800, Adrian Klaver wrote: > >>On 01/06/2014 03:18 AM, Martijn van Oosterhout wrote: > >>>Hoi, > >>> > >>> > > > >I'm not sure what you mean, isn't this the recommended way of doing > >things? The configuration comes from here: > > > >http://wiki.postgresql.org/wiki/Hot_Standby > > > >The master saves the archives to a directory, rsync copies them to > >the slave, where there restore_command can find them. > > Well this is the above is where is could be redundant. In your > original post it would seem the archive_command and restore_command > are pointing at the same directory. I realize they are just > placeholder names, so is that the case? If so I am not sure what > the rsync accomplishes. If not why not just make it so? Well, they're the same directory on different machines. The directory is actually /var/lib/postgresql/9.2/xlogs on both, but that's not really relevent. There's a cronjob on the master that says: rsync -avz /var/lib/postgresql/9.2/xlogs/* slave:/var/lib/postgresql/9.2/xlogs/ The question is: what is it that prevents the WAL files in /var/lib/postgresql/9.2/xlogs from filling the disk on the master? > The minimal cover your bases setup is usually given as: > > > Primary(Machine1) --> Archive --> Archive Directory(Machine2) > | | > | Streaming Restore | > -> Standby(Machine3) < - > > Excuse the ASCII art. The ascii art is fine, but you have the same problem: on the Machine1 the WAL files are stored prior to copying to Machine2. How do you know when you can delete files safely on Machine1? Anyway, I found this page on the wiki: http://wiki.postgresql.org/wiki/Binary_Replication_Tutorial which says that: archive_command = 'rsync -a %p 192.168.0.2:/var/lib/pgsql/data/archive/%f' is acceptable and also avoids the problem. I'll just test what happens with network failure (hopefully it doesn't kill the master). Have a nice day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > He who writes carelessly confesses thereby at the very outset that he does > not attach much importance to his own thoughts. -- Arthur Schopenhauer
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