Re: UFS2 Snapshots and Postgres

At 15:16 25/06/2012, you wrote:


>On 6/25/2012 7:35 AM, Eduardo Morras wrote:
>>
>>Hi everyone,
>>
>>I'm using FreeBSD 9 for Postgres and want to know if these actions
>>are safe for make a backup of the database:
>>
>>a) call pg_start_backup('b1')
>>b) take an UFS2 snapshot of data files
>>c) call pg_stop_backup()
>>d) change to the snapshot dir and rsync/dd/dump/transfer it to
>>backup file server
>>
>>Is it safe to call pg_start_backup('b1',true)?
>>
>>Thanks in advance
>Snapshots are "safe" (but will result in a roll-forward on restart)
>IF AND ONLY IF the log data and database table spaces are all on the
>same snapshotted volume.
>
>IF THEY ARE NOT then it will probably work 95% of the time, and the
>other 5% it will be unrecoverable.  Be very, very careful -- the
>snapshot must in fact snapshot ALL of the involved database volumes
>(log data included!) at the same instant.

Even if i do a pg_start_backup()? I thought it set db data/ files in
a consistent state and puts in wal files the new transactions and
apply them when call pg_stop_backup().

I must do it other way then :(

Thanks