Re: partitioning os swap data log tempdb

On Mon, 24 Feb 2003, Schaefer, Mario wrote:

> Hi,
> 
> we want to migrate from MS SQL Server (windows2000)
> to PostgreSQL (Linux) :-))
> and we want to use the old MSSQL Hardware.
> 
> Dual Pentium III 800
> 1 GB RAM
> 2 IDE 10 GB
> 2 RAID Controller (RAID 0,1 aviable) with 2 9GB SCSI HDD
> 1 RAID Controller (RAID 0,1,5 aviable) with 3 18GB SCSI HDD
> 
> The configuration for MS-SQL was this:
> OS on the 2 IDE Harddisks with Software-RAID1
> SQL-Data on RAID-Controller with RAID-5 (3 x 18GB SCSI Harddisks)
> SQL-TempDB on RAID-Controller with RAID-1 (2 x 9GB SCSI Harddisk)
> SQL-TransactionLog on RAID-Controller with RAID-1 (2 x 9GB SCSI Harddisk)
> 
> Can i make a similar configuration with PostgreSQL?
> Or what is the prefered fragmentation for
> operatingsystem, swap-partition, data, indexes, tempdb and transactionlog?
> 
> What is pg_xlog and how important is it?
> 
> What ist the prefered filesystem (ext2, ext3 or raiserfs)?
> 
> We want to use about 20 databases with varios size from 5 MB to 500MB per
> database
> and more selects than inserts (insert/select ratio about 1/10) for fast
> webaccess.

With that ratio of writers to readers, you may find a big RAID5 works as 
well as anything.

Also, you don't mention what RAID controllers you're using.  If they're 
real low end stuff like adaptec 133s, then you're better off just using 
them as straight scsi cards under linux and letting the kernel do the 
work.

Can you create RAID arrays across multiple RAID cards on that setup?  if 
so, a big RAID-5 with 4 9 gigs and 3 more 9 gigs from the other 3 drives 
might be your fastest storage.  That's 36 gigs of storage across 7 
spindles, which means good parallel read access.

How many simo users are you expecting?