Tom Lane wrote: > Dan Gorman <dgorman@xxxxxxx> writes: >> All of our databases are on NetApp storage and I have been looking >> at SnapMirror (PITR RO copy ) and FlexClone (near instant RW volume >> replica) for backing up our databases. The problem is because there >> is no write-suspend or even a 'hot backup mode' for postgres it's >> very plausible that the database has data in RAM that hasn't been >> written and will corrupt the data. > Alternatively, you can use a PITR base backup as suggested here: > http://www.postgresql.org/docs/8.2/static/continuous-archiving.html I think Dan's problem is important if we use PostgreSQL to a large size database: - When we take a PITR base backup with hardware level snapshot operation (not filesystem level) which a lot of storage vender provide, the backup data can be corrupted as Dan said. During recovery we can't even read it, especially if meta-data was corrupted. - If we don't use hardware level snapshot operation, it takes long time to take a large backup data, and a lot of full-page-written WAL files are made. So, I think users need a new feature not to write out heap pages during taking a backup. Any comments? Best regards, -- Toru SHIMOGAKI<shimogaki.toru@xxxxxxxxxxxxx> NTT Open Source Software Center
