> Greetings, > > * Zwettler Markus (OIZ) (markus.zwett...@zuerich.ch) wrote: > > with Oracle we use "backup archivelog all delete all input". > > this is a kind of atomic transaction. > > everything backuped for sure is deleted. > > > > with Postgres we archive to a local host directory > > ... how? Do you actually sync the files after you copy them with an fsync to > be > sure that they're durably stored there? If not, then there's a pretty good > chance > that you'll lose some WAL if a crash happens because if your archive command > returns successful, PG will removed its copy of the WAL file. > > Hint: using 'cp' as an archive command is a very bad idea. > > > we do a Networker backup of this directory afterwards and delete the > > archived logs but this is not an atomic transaction so there is a > > small risk that something gets deleted which is not backuped > > That would definitely be quite bad, particularly if a WAL file that was > needed for a > backup to be consistent was removed or missed, as that backup would no longer > be valid then. > > > how to you prevent this? > > I would strongly recommend that you use a tool that's actually built for the > purpose > of backing up PG systems, like pgbackrest or similar. > Writing your own custom code for managing WAL archives and backup sets is > likely to result in issues. > > > Is there any backup tool which can do backups analogous Oracle? > > There's quite a few different tools available for backing up PG systems, with > various features and performance- from simple things like pg_basebackup (which > you can set up to include all the WAL for the backup to be consistent, though > that > doesn't do anything to help you with managing WAL for PITR), to much more > sophisticated tools like pgbackrest, wal-g, and others that help with managing > WAL and dealing with expiring out backups and such. The biggest thing is- > don't > try to roll your own. > > Thanks, > > Stephen
We use "rsync" on XFS with "wsync" mount mode. I think this should do the job? The tools mentioned will all do backup to disk. We are required to do backup to tape. Markus
