Ühel kenal päeval, N, 2007-09-06 kell 19:33, kirjutas apoc9009:
> Simon Riggs schrieb:
> > I'm not clear whether you are looking for Backup, or High Availability
> > Replication.
> >
> > There is no data loss with the online backup technique described in the
> > manual.
> >
> No, there is a lost of Data.
>
> The WAL File musst bei generated by the Postmaster and this File must be
> copied to the
> safe Remote Backupserver. If the Machine, where the Database is running
> crashed, then the Last
> WAL is lost and the Backup isnt complet,e this is the Center of the Problem.
read and re-read 23.4.4
you DO NOT have to wait for the whole file to be complete to copy it
over
you can query the position where postgres has currently completed
writing and then copy over that part. doing so you can have wal-based
backup that is good up to last second (if you poll the function and copy
over the newly written part of the file every second)
Look at WalMgr.py in SkyTools package how this can be done in practice.
Skytools is available at http://pgfoundry.org/projects/skytools/
If used for setting up WAL-based backup on pg 8.2, it runs automatically
in "syncdaemon" mode, which means that parts of WAL file are copied over
as soon as they are written by postgres.
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Hannu