Re: Quick Survey

Joe Pluta wrote:
> Would you choose:
>
> 1. RAID 1
> 2. RAID 5
> 3. Other
>
> Why?

I chose mirroring for the traditional reason that it takes a mirrored pair
failure to lose an asp which means I could theoretically lose half the
drives in the asp and still operate.  There's also the possibility of
losing a controller and still being able to operate if you have that
protection level available.

I've also found a few other reasons that point to mirroring being superior:

1) we had some large (non-ibm) drives on our 730 that would require 14
hours to build a parity set, but only 5 hours to mirror -- that means that
the system would be available 9 hours earlier in a disaster situation if we
went mirroring instead of parity.  During one of my "trials by fire" I
decided to go without protection at all because I couldn't have the delay
induced by the 14 hour build (the system crashed every time we tried to
mirror these drives in asp 1).

2)  if a drive has a temporary failure, the system will automatically
resume the mirrored pair (which would usually take less than an hour) once
the drive becomes responsive, while a parity set must be restarted via SST
(which would take 12 hours).

Bill