Re: Booting from SAN or local?
- From: "Chuck Timon [MSFT]" <ctimon@xxxxxxxxxxxxx>
- Date: Wed, 28 Sep 2005 13:37:13 -0400
Be sure you review
http://support.microsoft.com/default.aspx?scid=kb;[LN];305547 and understand
that booting from a SAN must be supported by the hardware vendor or
Microsoft will not support it.
--
Chuck Timon, Jr.
Microsoft Corporation
CCS Beta Engineer
This posting is provided "AS IS" with no
warranties, and confers no rights.
"Ryan Sokolowski [MVP - Avanade]" <ryan@xxxxxxxxxxxxxxxxxxxxxx> wrote in
message news:%23CtRmy6wFHA.1488@xxxxxxxxxxxxxxxxxxxxxxx
> I'll add this point also. Make sure you're using the correct (read:
> STORPORT) drivers for your HBAs and ensure they're configured properly
> (firmware, settings, etc.). Work with your storage vendor if you wish /
> must.
>
> Since the system disks are SAN-based, everything now depends on the
> performance of your Fibre Channel zoning, HBAs, drivers, physical layer
> (cabling), etc....
>
> --
> Ryan Sokolowski
> MVP - Windows Server - Clustering
> MCSE, CCNA, CCDA, BCFP
> Avanade
> http://www.Avanade.com
>
> "A troubleshooter's best tool is the Event Viewer and understanding the
> events and messages contained therein."
>
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>
> "Russ Kaufmann [MVP]" <russ@xxxxxxxxxxxxxxx> wrote in message
> news:%23sh18S6vFHA.1988@xxxxxxxxxxxxxxxxxxxxxxx
>> "Matt Povey" <Matt Povey@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:384D6D50-CF92-48B8-A2F8-48C61AC8EA33@xxxxxxxxxxxxxxxx
>>> 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
>>
>> That is a nice bit of functionality, but does not result in performance
>> increases unless the blades are using slow drives.
>>
>>> 2) DR. By synchronously replicating a boot volume across sites, you can
>>> massively simplify your DR process though the use of cold standby
>>> server.
>>
>> An excellent point if you have geographically disperse SANs that are
>> configured to synch. I agree that it is a great benefit.
>>
>>>> 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?
>>
>> If you look at this regarding strict I/O performance and data transfer,
>> which is capable of delivering uncached data quicker? I would counter
>> that the SAN throughput, even using multipathing, will be slower than
>> using local disk connecting using a local bus.
>>
>>> 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).
>>
>> Again, this is also a performance issue. Page file swaps will be much
>> quicker across a local bus than across the SAN fabric.
>>
>>>> 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.
>>
>> SANs utilize extremely high amounts of RAM for caching, so in most "read"
>> cases, cache hits more than make up for the lesser transfer rates. In
>> most cases, with file and SQL access, you will see other bottlenecks to
>> high performance.
>>
>>>> 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.
>>
>> I disagree with Matt on this one. DAS is capable of much greater transfer
>> rates than SAN attached drives.
>>
>>
>> --
>> Russ Kaufmann
>>
>> MVP - Windows Server - Clustering
>> http://www.clusterhelp.com - Cluster Website
>> http://msmvps.com/clusterhelp - New Blog
>> http://spaces.msn.com/members/russkaufmann - Old Blog
>>
>
>
.
- References:
- RE: Booting from SAN or local?
- From: Matt Povey
- Re: Booting from SAN or local?
- From: Russ Kaufmann [MVP]
- Re: Booting from SAN or local?
- From: Ryan Sokolowski [MVP - Avanade]
- RE: Booting from SAN or local?
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