Hi Steve,
Very interested to hear about your setup,
as I have a similar setup (backend to a mail server/SPAM scanner) although on a
much lighter load at the moment.
My database is only just touching a GB so
nothing near the scale of yours! I use a file-system level backup, and am
currently testing a PITR continuous recovery onto a hot-standby server.
Tar-ing the database directory currently
takes about a minute (at 1GB), so as you can estimate it’d be about 3 hours
for yours.
My future plan for when my database grows
larger, is with the use of WAL logging – have a base backup taken on a
Sunday morning (our quietest time), ship this to the hot-standby once a week,
and start it off in a recovery mode (using my rolling-WAL script I’m
testing now.) Then throughout the week, send the WAL logs from the live
box as they become available down to the standby, which then get processed on
arrival – these files are 16MB in size (I believe this can be changed).
The beauty of all this is it doesn’t
require the database to be taken off-line, or slowed down.
This is coming from an 8.1 server, I
believe it’d be okay for 7.4 but don’t quote me on it.
Regards
Andy
From: pgsql-admin-owner@xxxxxxxxxxxxxx
[mailto:pgsql-admin-owner@xxxxxxxxxxxxxx] On
Behalf Of Steve Burrows
Sent: 28 April 2006 4:58 pm
To: pgsql-admin@xxxxxxxxxxxxxx
Subject: [ADMIN] Backing up large
databases
I am struggling to find an
acceptable way of backing up a PostgreSQL 7.4 database.
The database is quite large, currently it occupies about 180GB, divided into
two elements, a set of active tables and a set of archive tables which are only
used for insertions.
I ran pg_dump -Fc recently, it took 23.5 hours to run, and output a single file
of 126GB. Obviously as the database continues to grow it will soon be so large
that it cannot be pg_dumped within a day. Running rsync to do a complete fresh
copy of the pgsql file structure took 4 hours, but later that day running
another iteration of rsync (which should have only copied changed files) took 3
hours, and I cannot afford to have the db down that long.
Anybody with any ideas? The database is being used as the backend for a mail
server, so it has transactions 24 hours a day but is quieter at night. I want
to be able to back it up or replicate it on a daily basis with minimum downtime
so that the mail backlog doesn't get too large. Ideally I want the first
generation of backup/replica going onto the same machine as the original
because the volume of data is such that any attempt at network or tape backup
of the live files will require too much downtime, once I've got a backup then I
can copy that out to other NAS or tape at leisure.
If anyone has experience of safeguarding a similarly large PostgreSQL database
with minimal downtime I'd be delighted to hear.. The machine is running 2
Xeons, 4GB ram and a half-terabyte RAID10 array on a DELL PERC scsi subsystem,
with a load average of around 0.5 - 0.6, so it's not exactly overstretched.
Thanks,
Steve
!DSPAM:14,4452344633691957362147!
