Tuesday, 7 September 2010

On Board Software “RAID” No More

We stopped using the on board “RAID” feature of on all of our client servers.


Because the cost of a high performance 4 port RAID controller like the Intel RAID Controller RS2BL040 is under $450CA.

For $450 we get:

  1. True RAID on Chip driven calculations.
    • No software interpreting the RAID calculations on the CPU.
  2. Drive redundancy.
    • But, on board RAID is just that: RAID right? Well, no. If a drive fails in an on board based “RAID” array 9 times out of 10 the server is locked up.
    • If a drive fails on a true RAID controller based array the RAID controller marks the drive dead, logs the failure, but _keeps moving along_.
  3. Data Protection
    • We have seen more failed OS loads after an on board based “RAID” array member failure by a factor of at least 10 compared to either a member or RAID controller failure in server settings.
  4. Performance
    • On board RAID relies on the software drivers to do all of the calculations. They run on top of the CPU. There is a performance hit for this.
    • Add a battery backup for the RAID on Chip’s memory cache and the array performance steps up accordingly.
    • Array rebuild times to hot spare for the RAID on Chip solution will be superior to on board software “RAID”.
      • A failed drive is when the server is most vulnerable.
  5. Maintenance
    • RAID on Chip solutions offer true hot swap compatibility.
    • Some software “RAID” setups may offer the same. But, test it first.

Given the overall benefits of an add-in RAID solution, in our opinion, no server should go out the door with an on board software “RAID” setup.

It is just not worth the risk.

Adaptec also makes some pretty good RAID on Chip solutions.

Philip Elder
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book

*Our original iMac was stolen (previous blog post). We now have a new MacBook Pro courtesy of Vlad Mazek, owner of OWN.

Windows Live Writer

No comments: