SAN and SQL Performance

Our company needs and will be moving to SAN environment.
I have a DELL 6650 with 16 gig of memory and 5 ative Perc 320 channels
with 15k rpm drives. There is about 5 drives on each channel in a raid
5 array. The databases are split across the channels to improve
performance because the servers are I/O bound. Moving from 8 gig to 16
gig of memory gave a 10 - 20% performance boost. The servers are Win
2003 running SQL 2k. The largest database is about 45 gig of data of
which about 5% is updated or added on daily basis and about 25% is
updated on each Sunday. The data updates come from the Access database
mentioned below.
There are SQL 2 other servers similarly configured.
There are several other smaller sql servers that I have no doubts would
benefit from the SAN.
The san would probably have at least 2 or 3 hundred gig of sql data plus
several hundred gig of other data files, exchange... Access is very
heavily used here. There are probably about 90 Access databases many
with over 500 meg of info in them.
I am not looking for SAN design. I just have concerns that the SAN will
not deliver up data as fast as the locally attached storage. Especially
when I toss in the competition from the other sql servers and the users.
I have been told that that the SAN will not only be able to replace the
current setup but will dramatically improve the current I/O performance.
Is that what you have seen in your experiences?
I know the SAN has benefits for the other data and welcome the SAN. We
run into way to many storage issues now that the SAN will solve.
Thanks for your feedback,
Ron> I am not looking for SAN design. I just have concerns that the SAN will
> not deliver up data as fast as the locally attached storage.
As long as you use fiber (or gig e) and reliable switches, you should see no
difference between local and network access. It's when you expect 10mb or
even 100mb to replicate performance of local drives where you get
disappointed.
At least that's our experience, with EMC Clariion (currently 10 TB).
You should use redundant HBAs as well, if you can...
Of course, we can't see your configuration, so other than relying on our
guessing, the best thing you can do to see if your concerns are reasonable,
is to TRY IT.
--
Aaron Bertrand
SQL Server MVP
http://www.aspfaq.com/|||Thanks for the feedback.
Testing is going to be done.
"Aaron Bertrand - MVP" <aaron@.TRASHaspfaq.com> wrote in
news:uC2dtG0vDHA.560@.TK2MSFTNGP11.phx.gbl:
>> I am not looking for SAN design. I just have concerns that the SAN
>> will not deliver up data as fast as the locally attached storage.
> As long as you use fiber (or gig e) and reliable switches, you should
> see no difference between local and network access. It's when you
> expect 10mb or even 100mb to replicate performance of local drives
> where you get disappointed.
> At least that's our experience, with EMC Clariion (currently 10 TB).
> You should use redundant HBAs as well, if you can...
> Of course, we can't see your configuration, so other than relying on
> our guessing, the best thing you can do to see if your concerns are
> reasonable, is to TRY IT.
>