Which SCHED_ for DB server
hk at alogis.com
Thu Sep 1 07:58:55 GMT 2005
On Thu, Sep 01, 2005 at 04:54:52PM +1000, Norberto Meijome wrote:
> I'm building a server that will run PostgreSQL with a database
> containing several 10s of million records. The only things happening on
> this box will be the SQL processes and other processes to parse raw data
> and load into the DB. Users = a few connections via HTTP from an
> intranet server (not more than 5 concurrently).
> I was wondering what is the best SCHED_ to set in the kernel.
> I currently have SCHED_4BSD but was wondering if _ULE would be better
> for this
I would not care that much about the scheduler you want to use. In worst
case, recompile the kernel and look at performance / userinteraction.
What looks worse (imho) is this:
> 4 x SATA 150 drives, 90% of it RAID5 with gvinum.
I do not know your applications, but if writing to disk is an issue:
- WAL-files should be written to physically separated disks.
- Write performance to RAID5 is not very good (tm).
This is both with softraid and with hardware raid, although
those raid controllers with 64MB or higher (+batterybackup)
might increase the visible performance if only a few processes
- ATA is not good for production - better use SCSI.
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