Patrick Dung wrote: > I have some questions about backup on PostgreSQL: > > 1) pg_dumpall > I am sure that this is asked in somewhere: why the pg_dumpall does not support custom or tar format > like pg_dump. > I have heard that the custom format could be faster and may generate a smaller dump file. > Is the feature enhancement being developed? I suspect that the reason is that pg_dumpall just calls pg_dump and concatenates the output, and that probably only works in text format. > 2) pg_start_backup in postgresql 8.4 > After issuing pg_start_backup, we can take the file based backup (by tar/snapshot) on the postgresql > data directory. > If the use of file system snapshot is not possible. I don't understand this sentence. > It is possible that there is file changes (added or file size changed) between the pg_start_backup and > pg_stop_backup. Yes. > Is the backup consistent? The tar or snapshot itself will not be consistent, it will have to be recovered at least until the end on the online backup. > 3) extension of 2): If the postgresql version is 9.2 > Is pg_basebackup better than pg_start_backup + file based backup + pg_stop_backup? Technically they are equivalent. pg_basebackup may be easier to use, the other option may provide more flexibility. One difference is that there can be many pg_basebackups running at the same time. > 4) For the WAL backup in postgresql 8.4 > After the archive mode is on and WAL is backup, how do I remove the old WAL files? > How about newer version (for example 9.2?) You never touch the files in pg_xlog on a running server. You remove old WAL archives when you don't need them any more. Usually that is when there is no older base backup. Yours, Laurenz Albe -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
