Alan Hodgson wrote:
> On Thursday 28 August 2008, Shane Ambler <pgsql@sheeky.biz> wrote:
>> If you have a filesystem backup from 6 hours ago, then the WAL
>> files as they are now can be used to update the backup to match the
>> db as it is now. This makes the filesystem backup have two points
>> of interest. First the entire data folder. Second the WAL files.
>> You may backup the entire data folder maybe once a day (or week?)
>> but you would also want to backup the WAL files maybe every 15
>> mins.
>
> No, no. Completed WAL files will be archived automatically as part of
> the PITR backup strategy. Just backing up WAL files from pg_xlog
> isn't useful. The files get overwritten constantly.
>
>
OK probably not worded well.
I was referring to *all* WAL data since the snapshot was taken.
This may be the pg_xlog contents if the snapshot was very recent but
would more likely be the archived collection generated from the
archive_command setting.
Saying to backup the WAL every 15 mins is more symbolic of an automated
backup script running that would save the archived files to tape or
whatever backup medium is being used.
--
Shane Ambler
pgSQL (at) Sheeky (dot) Biz
Get Sheeky @ http://Sheeky.Biz
