Tuesday, January 19, 2010

Storage fundamentals

Throughput part 1: The Basics

Throughput part 2: RAID types and segment sizes

RAID 10 or RAID 5

This is a common question in every storage consultation. Right answers for such questions is - It depends. Lot of people don't like RAID 5 and they have good reasons ... Look at BAARF (http://www.baarf.com/) initiative Battle Agains Any RAID Five, Four, F(T)hree. Very nice RAID5 versus RAID10 comparison is at http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt

I think that good choice depends on required performance, capacity, and data value stored on protected disks. RAID is just one type of protection and other protections should be used. Other data protections are:
  • Backup
  • Local Disk Replication (Volume Clones - Business Continous Volumes like i.e. EMC SnapView)
  • Remote Disk Replications (EMC SAN Copy, EMC SRDF, IBM Metro Mirror, etc.)

So sometimes RAID 5 or 6 makes sense.