Re: WAL files backup - Mailing list pgsql-admin

Chad Wagner wrote:

On 2/15/07, Eduardo J. Ortega <ejortegau@cable.net.co> wrote:

After erasing the "less than  names" WAL files, we add to tar the remaining
WAL records (0003B, 0003C  and so on on the example). The more WAL files you
have after 0003B, the more up to date DB you get after restore (since it has
more WAL files indicating more transactions that took place after the backup.

Why bother trying to delete WAL files older than the .backup file?  When PostgreSQL is in recovery mode it knows which WAL files are necessary to perform the recovery.

Also, the documentation recommends excluding the pg_xlog directory when performing the base backup.  Likely when it comes time to recovery the online WAL files have been archived already, so it is a risk of confusion I am sure.

If the OP is doing the same as myself, the WAL files are being archived outside of pg_xlog (indeed outside of the PG data cluster) - it makes no sense keeping around WAL files older than the .backup file because they're not needed - in a day I generate ~5GB worth of WAL files which aren't needed after the full backup runs at 2am, so it's a waste of resources to keep them around or to worry about backing them up after this time.

Andy.