Roger Hand wrote:
Due to performance issues (which I wrote about on pg-performance list) we will be upgrading our Redhat AS3.0 box (kernel 2.4) to Redhat AS4 (kernel 2.6) in order to take advantage of the better I/O that the 2.6 kernel offers. (I say upgrading but actually we'll wipe the box and start fresh.) We are running Postgres 8.0.3. I had assumed we would have to backup/restore the entire db, but I got to wondering if it would be possible to simply point the new Postgres install to the existing db (the data itself is on a separate drive array) and be back up and running without the time to do the restore.
Yes as long as you are not switching architectures (say to x86_64) or filesystems you should be fine. I assume you will be running 8.0.3
on the new system as well.
Is this a relatively simple matter? Or is it too hazardous and tricky to bother with?
Not hazardous at all as long as you don't accidently format the filesystem ;). Make a tar backup just in case.
If it's possible I'd appreciate a list of what I'd need to save off the old drive, where the os and Postgres program itself lived.
Nothing. The postgresql.conf and pg_hba.conf will reside in the data directory so it will be fairly independent. Note that I am ONLY talking about postgres here. You may want to save things from the OS for other reasons.
Also: Anything to watch out for with Postgres on 2.6 kernel as opposed to 2.4? Any settings that should be different? We've been advised to try "elevator=deadline". We write pretty much 24 hours a day, and have I/O issues!
Well 2.6 is pretty solid but I wasn't part of the thread so I can't tell you if this will solve your problem. I can
say that overall 2.6 is much better for databases. Sincerely, Joshua D. Drake Command Prompt, Inc.
-Roger
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