Hello,

I'm interested in using WAL shipping / replication for backup purposes but have 
no interest in failover. Currently my situation is:

I have two servers, live and backup, which are in different cities. The backup 
server is also a test/development machine.

Backups of my most important database are made hourly with pg_dump, excluding 
some larger tables with non-critical logging data. Even so, as the database 
grows, backups are taking longer and it looks as though they may start to 
impact performance. A full backup is made nightly and transferred to the backup 
machine, along with all of the day's hourly backups.

I'm looking into using replication by WAL shipping - after all, there's no use 
to backing up data which hasn't changed since last time - only a small 
percentage of records are created/updated. However, I need

a) to be able to restore to a point in time easily, which I can do to within an 
hour at the moment by restoring the correct dump. Sometimes users ask for a 
restore having accidentally updated/deleted records.
b) to carry on running a test server database, that means one that's read and 
writeable.

I obviously can't use a replication slave as a read/write test server at the 
same time. At the moment I've thought of a couple of options, I don't know if 
either are possible - I have a bit of a hazy idea of WAL replication.

1) Continuously ship the WAL records to somewhere on the test server unknown to 
Postgres but run the test machine as a normal database completely separately. 
If a backup is needed, delete the test database, restore to the last full 
backup (a filesystem backup?) and copy all WAL records into Postgres' directory 
so it can see them. Start it up configured to replay them, up to a certain time.

2) Run two instances of Postgres on the test/backup server on different ports, 
one configured as a replication slave, one normal. I'm not sure if this is 
possible with the RPM builds I'm using.

Are either of those two likely? Any other suggestions? Another question is will 
the replication coming in v9.0 change things and would it be worth holding off 
until then? In particular Command Prompt's PITR tools look useful for restoring 
to a particular point in time, will these still work or will there be 
equivalents?

Regards
Oliver Kohll

oli...@agilebase.co.uk / +44(0)7814 828608 / skype:okohll




-- 
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

Reply via email to