Re: Best setup for RAM drive

Why not just run PostgreSQL like everyone else does (from a hard drive) and
simply give it heaps of buffers - let PostgreSQL manage its RAM itself?

Unless you have your xlog on physical storage, you are asking for trouble.
Actually, unless you have all your database in physical storage, you are
asking for trouble! (At least until we have point in time recovery, but
that still requires you to have your xlog on hard drive)

Chris

----- Original Message -----
From: "Chris Sutton" <chris(at)smoothcorp(dot)com>
To: <pgsql-hackers(at)postgresql(dot)org>
Sent: Tuesday, March 04, 2003 11:03 PM
Subject: [HACKERS] Best setup for RAM drive

> Hello,
>
> I need some insight on the best way to use a RAM drive in a Postgresql
> installation. Here is our situation and current setup:
>
> Postgresql 7.2.1
> Dual PIII 800
> RAID 5 SCSI disks
> Platypus 8GB PCI QikDrive (the RAM drive). http://www.platypus.net
>
> The Platypus RAM drive is a PCI card with 8GB of ram onboard with an
> external power supply so if the main power to the server goes off, the RAM
> is still powered, so it's persistent between reboots.
>
> Currently the disk size of our database is 3.2GB, so we put the whole
> pgsql directory on the RAM drive. Current preformance is very
> snappy with the bottleneck being the CPUs.
>
> The concern of course is if something happends to the RAM drive we are
> S.O.L. and have to go to the last backup (pg_dump happens each night).
>
> The other concern is if the disk size of the database grows past or near
> 8gb, we would either have to get a bigger RAM drive or somehow split
> things betten SCSI and RAM drive.
>
> I don't quite grasp the full inner workings of Postgresql, but
> for those of you who obviously do, is there a better way of setting things
> up where you could still use the RAM drive for portions of the pgsql
> directory structure while putting the rest on disk where it's safer?
>
> Should we just put pgsql/data/pg_xlog on the RAM drive?
>
> Also, in the very near future we will be upgrading to another server,
> pg7.3.2 with dual P4 2.4 xenon's. The RAM drive will go into this new
> server.
>
> Any suggestions?
>
> Thanks
>
> Chris
>
>
>
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