SAN based storage

[Ben Carter]

Michael Loftis wrote:
> 
> 
> --On April 19, 2006 12:47:26 PM -0500 John Wade <jwade at oakton.edu> wrote:
> 
>> We run cyrus on RedHat on a CX600.  For our administrative users, we put
>> the whole thing on a nine disk fibre channel RAIDgroup, split into 6
>> luns, 5 for mail spool partitions and 1 for all the other metadata.
>> Total mail spool size is 300GB.   We average about 300 concurrent
>> users.   The CX600 is heavily used by other applications.       I/O
>> performance has never been an issue as far as I can tell.   The large
>> write caches in the CX600 solve the write problem and the host memory
>> caching seems to solve the read problem.    Your mileage may vary.     We
>> couldn't do a direct cyrus  SAN performance comparision because when we
>> moved to this box, we migrated to the SAN and new server hardware at the
>> same time,  but tests on other systems where we just moved storage on to
>> the array saw a huge performance boost vs. locally attached SCSI RAID 5
>> storage with no write cache enabled.
> 

If you're really building 9-disk RAID 5 RAID groups, you might see a
pretty big performance hit on a drive failure - until the data has been
rebuilt on the hot spare of course.  You might want to test this before
going this way.

-- 
Ben Carter
University of Pittsburgh/CSSD
bhc at pitt.edu
412-624-6470