On 3/29/06, Thomas F. O'Connell <tfo@xxxxxxxxxxxx> wrote: > I just want to make sure that I've got a good enough understanding of > the built-in on-line backup facility to be able to minimize data loss > and unavailability of the database during a remote recovery from on- > line backup. > > Here are the steps I'm proposing: > > 1. Set up archive_command in postgresql.conf on oldhost to archive to > remote repository on newhost. > 2. Perform base backup on oldhost. (I'll probably just use rsync to > backup directly to newhost.) > 3. On newhost, remove postmaster.pid from $PGDATA, disable > archive_command in postgresql.conf, and create clean pg_xlog tree. > 4. Stop the postmaster on oldhost. > 5. If the WAL file referenced by the backup file in my archive > directory on newhost is not archived when the postmaster is stopped, > copy it from oldhost to pg_xlog on newhost. even if it(STOP WAL) was archived in the new machine , you should also copy the last partially filled WAL log from pg_xlog that was created just after the file refrenced in backup file was archived. I think the overall process is fine , you may consider executing a test run skipping 4 Regds Rajesh Kumar Mallah. > 6. Create recovery.conf on newhost. > 7. Start the postmaster on newhost. > 8. Rejoice when recovery.done appears. > > The part I most want to make sure I understand well enough is step 5, > which I'm understanding to be a modification of steps 2 and 6 from > section 23.3.3 in the docs. As I understand it, there's a pretty good > possibility that the WAL file referenced by stop_backup() will not be > archived by the time I stop the postmaster on oldhost. In which case, > I should be in good shape to recover if I have a base backup, the > archived WAL files up to that final file referenced by stop_backup(), > and the partial segment file referenced by stop_backup(), which > should be the only unarchived WAL segment file and just needs to > exist in pg_xlog on newhost for things to run smoothly. > > Does this seem right? Or will I rather want to copy all the contents > of pg_xlog from oldhost as they represent current (as of stopping the > postmaster) unarchived WAL activity? > > -- > Thomas F. O'Connell > Database Architecture and Programming > Co-Founder > Sitening, LLC > > http://www.sitening.com/ > 3004 B Poston Avenue > Nashville, TN 37203-1314 > 615-260-0005 (cell) > 615-469-5150 (office) > 615-469-5151 (fax) > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: Have you checked our extensive FAQ? > > http://www.postgresql.org/docs/faq >
