We use a storage virtualization system with diskless servers booting from external disks. When determining what RAID level to use, we had no real grasp of how our applications and/or servers accessed the disk. By this I mean, what is the ratio of reads vs. writes?
After migrating to our storage system we were able to use monitoring tools to see the number of reads vs. writes. In this case, we noticed that our NetWare file and print servers had significantly more writes on the SYS volume. The other volumes had more reads.
With storage virtualization we are able to separate our SYS volume from all other volumes. To optimize performance, our SYS volumes are RAID 10 and our other volumes are RAID 5.
Our NT servers have a similar setup. The C: drive partition is RAID 10, while the other partitions are RAID 5. This allows us to take advantage of the faster writes on RAID 10 while not spending a fortune in disk space to make everything RAID 10.
About the author: This tip was written by Brin Kjenstad.
This was first published in February 2001