There is one caveat Mark.

If the loss of a backup is a critical failure to an application, then you
must Raid-1 or Raid-5 the pool.  I have applications that take processing
cycle backups several times throughout their processing cycle.  I also have
servers that have to have the same backup cycle.  So, an unprotected
diskpool is not a black or white answer to solving a performance problem.

However, you are correct, RAID-5 is going to perform like crap for disk
pools unless you have ESS disk which have a very large disk cache on the
front and the RAID-5 turns into RAID-3 (no reads before writes because it is
always a full stripe write).

Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180