Re: Mirroring, Striping, Etc.

Dale E. Reed Jr. ( (no email) )
Tue, 03 Feb 1998 00:59:08 -0800

Gregory White wrote:
>
> Can someone offer some information regarding performance
> improvements/degradation caused by drive mirroring and striping on NT 4?
>
> We recently added a second drive to our mail server and set it up as a
> mirror drive. Since then, it seems to be slower in responding when sending
> mail. It may just be perception, since I am paying more attention to the
> machine now.
>
> We are running a PP150 w/128 MB Ram and 2- 2.1 GB SCSI on an Adaptec 2940.

Mirroring will slow the disk access down for writing. Reading
should be negligible (possibly faster). I tested two wide scsi
two drives on a Cyrix 166 box w/64mb of memory. With a single drive
I would sustain 9mb/second reading from a sequential 512mb file and
and 4mb/sec random. Striping two drives took the performance to
about about 15 and 6, respectively. So the performance did improve
with the striping. We do a lot of mirroring with drives for SQL Server
and production servers for the fault tolerance, and its saved us
more than once. 

-- Dale E. Reed Jr.  (daler@iea-software.com)_________________________________________________________________       IEA Software, Inc.      |  RadiusNT, Emerald, and NT FAQs Internet Solutions for Today  |   http://www.iea-software.com