I need a Server to support 20 - 25 users with SAS RAID

but budget is bit limited...

My thinking is :

2 x SATA drives - RAID 1 for OS {not onboard sata controller}
2 x SAS 146 or 300 15K RPM for data using NSS

With Netware I tended to use Software RAID with SCSI drives where budget is

does OES support Software RAID ??

ie. OS with EXT3 - software Raid
Data with NSS - Software Raid

If hardware which controller are supported by OES11 ?
out of the box and after patching !!