RE: Booting from SAN or local?

Shane,

I disagree with the other guys here. While I see their points, there are
specific situations where using boot from SAN for Windows servers is
extrememly beneficial.

In particular, if you're operating in one of the following environments,
it's very helpful :

1) Rapid deployment \ blade environments - SAN boot volumes can be
re-assigned \ copied dynamically within the SAN fabric aiding fast deployment
and recovery from localised hardware failures

2) DR. By synchronously replicating a boot volume across sites, you can
massively simplify your DR process though the use of cold standby server.

Answers to your other questions below :

"Shane" wrote:

> My question to the group is: What is the preferred method of booting. My
> opinion is it would be local with a mirrored disk seeing as booting up off
> the SAN is really slow.

You really shouldn't be seeing any performance problems booting from SAN. If
performance from your data volumes is adequate but the boot disk is poor I'd
look at the BIOS currently installed on your HBA. Is your environment
qualified end to end by your SAN vendor?

You really shouldn't have your page file on SAN attached disk although this
is really for availability\reliability reasons rather than performance
(although it's a waste of SAN resources to have the page file there).

>
> Does having the system disk on the SAN slow things down in a SQL and file
> sharing cluster environment?
>

It certainly shouldn't do. Once booted, a Windows server with sufficient RAM
doesn't really touch the boot disk. Even if it did, access to SAN attached
disk should be as fast and low latency as DAS. Note that sync rep, SAN based
mirrors , snaphots etc. can have an effect on performance.

The clusters I've got booting from SAN (file, print and Exchange all in AAAP
conf.) all perform just fine.

> Any ideas would be great as I think doing the disks local would have
> performance advantage but I would need to produce something to management.
>

There's no reason to think that you'll get a useful performance advantage
from DAS (depending on the configuration of your SAN of course) and you'll
likely lose significant functionality by switching to local disk.

> Cheers
>
> Shane

You should read the following :

http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/clustering/storbp.mspx
http://support.microsoft.com/default.aspx?scid=kb;en-us;305547
http://support.microsoft.com/kb/309186/EN-US/
http://support.microsoft.com/kb/301647/
http://support.microsoft.com/default.aspx?scid=kb;en-us;304415

Good luck,

Matt Povey

.

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