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Working with a SAN for 2-4 TB database

Author
17 Mar 2006 6:40 PM
Randy K
My agency is configuring its first SAN, a IBM DS4000.  None of our
staff know the best way to configure it for use wtih SQL Server 2000.
I haven't been able to find any white papers or SANS forums to bring
myself, as DBA, up to speed.  Any recommendations?

Now for a specific question.  The IBM tech has told our hardware folks
to sent up one 2TB LUN for our orthophoto database.  A few users on
this forum suggest breaking that up into multiple LUNs.  By next year
we will have added another 2 TB for the growth of that database.   Is
there a way to present multiple LUNs as one attach point for SQL
Server or will it be one drive letter assignment for each LUN?

Author
18 Mar 2006 1:32 PM
Dan Guzman
See http://support.microsoft.com/kb/819546/en-us.

The bottom line is that SQL Server 2000 supports mount points, but not with
clustering.   SQL Server 2005 fully supports mount points.


--
Hope this helps.

Dan Guzman
SQL Server MVP

Show quoteHide quote
"Randy K" <waw***@hotmail.com> wrote in message
news:441b007f.3113640@msnews.microsoft.com...
> My agency is configuring its first SAN, a IBM DS4000.  None of our
> staff know the best way to configure it for use wtih SQL Server 2000.
> I haven't been able to find any white papers or SANS forums to bring
> myself, as DBA, up to speed.  Any recommendations?
>
> Now for a specific question.  The IBM tech has told our hardware folks
> to sent up one 2TB LUN for our orthophoto database.  A few users on
> this forum suggest breaking that up into multiple LUNs.  By next year
> we will have added another 2 TB for the growth of that database.   Is
> there a way to present multiple LUNs as one attach point for SQL
> Server or will it be one drive letter assignment for each LUN?
>
>
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Author
20 Mar 2006 8:42 AM
Steen Persson (DK)
Randy K wrote:
Show quoteHide quote
> My agency is configuring its first SAN, a IBM DS4000.  None of our
> staff know the best way to configure it for use wtih SQL Server 2000.
> I haven't been able to find any white papers or SANS forums to bring
> myself, as DBA, up to speed.  Any recommendations?
>
> Now for a specific question.  The IBM tech has told our hardware folks
> to sent up one 2TB LUN for our orthophoto database.  A few users on
> this forum suggest breaking that up into multiple LUNs.  By next year
> we will have added another 2 TB for the growth of that database.   Is
> there a way to present multiple LUNs as one attach point for SQL
> Server or will it be one drive letter assignment for each LUN?
>
>
Hi Randy

What should be the purpose of having several LUN's ? Unless somebody can
come up with any specific reason for splitting it up, I'd listen to the
IBM guys and set it up like they suggest.


Regards
Steen
Author
21 Mar 2006 9:43 PM
Randy K
Steen,
  The concern expressed by our GIS vendor is that  the longer the
recovery takes the more risk we assume that another disk will fail
during recovery which would be 'fatal' so to speak (i.e. back to
tape).

SATA drives are not as robust so they may have a higher failure rate.

Randy

On Mon, 20 Mar 2006 09:42:11 +0100, "Steen Persson (DK)"
<s**@REMOVEdatea.dk> wrote:

Show quoteHide quote
>Randy K wrote:
>> My agency is configuring its first SAN, a IBM DS4000.  None of our
>> staff know the best way to configure it for use wtih SQL Server 2000.
>> I haven't been able to find any white papers or SANS forums to bring
>> myself, as DBA, up to speed.  Any recommendations?
>>
>> Now for a specific question.  The IBM tech has told our hardware folks
>> to sent up one 2TB LUN for our orthophoto database.  A few users on
>> this forum suggest breaking that up into multiple LUNs.  By next year
>> we will have added another 2 TB for the growth of that database.   Is
>> there a way to present multiple LUNs as one attach point for SQL
>> Server or will it be one drive letter assignment for each LUN?
>>
>>
>Hi Randy
>
>What should be the purpose of having several LUN's ? Unless somebody can
>come up with any specific reason for splitting it up, I'd listen to the
>IBM guys and set it up like they suggest.
>
>
>Regards
>Steen
Author
22 Mar 2006 9:37 AM
Steen Persson (DK)
Randy K wrote:
> Steen,
>   The concern expressed by our GIS vendor is that  the longer the
> recovery takes the more risk we assume that another disk will fail
> during recovery which would be 'fatal' so to speak (i.e. back to
> tape).
>
> SATA drives are not as robust so they may have a higher failure rate.
>
> Randy

Hi Randy

I'm not an expert on LUN's but I've never heard that it should make a
difference in relation to rebuilding time. In our setup our biggest
arrary is 24 disks in a RAID 5 assigned a single LUN and we've never
experienced any problems. When you have to rebuild/replace a disk it's
in my opinion the number of disks in the whole array that makes a
difference. I know that (some) IBM storages  (and maybe other vendors as
well) have the ability to have e.g. 2 RAID 5 arrays acting as one
towards the OS. I don't know if this is what you're talking about? We
have talked to IBM about this for some time ago, but they didn't really
recommended this solution.
I can't remember the exact reason, but I think it was something like it
didn't really gave any improvement of performance but in turn it added
some unnecessary complexity to the setup.

BTW: It was my understanding that LUNs was only relevant when talking
about SCSI disks and not ATA/SATA disks, but apparently I'm wrong?

Regards
Steen
Author
22 Mar 2006 5:16 PM
Randy K
Hi Steen,
  We are using SATA drives because they are cheaper and the fact that
our data is very static since it is orthophotography.

On Wed, 22 Mar 2006 10:37:45 +0100, "Steen Persson (DK)"
<s**@REMOVEdatea.dk> wrote:

Show quoteHide quote
>Randy K wrote:
>> Steen,
>>   The concern expressed by our GIS vendor is that  the longer the
>> recovery takes the more risk we assume that another disk will fail
>> during recovery which would be 'fatal' so to speak (i.e. back to
>> tape).
>>
>> SATA drives are not as robust so they may have a higher failure rate.
>>
>> Randy
>
>Hi Randy
>
>I'm not an expert on LUN's but I've never heard that it should make a
>difference in relation to rebuilding time. In our setup our biggest
>arrary is 24 disks in a RAID 5 assigned a single LUN and we've never
>experienced any problems. When you have to rebuild/replace a disk it's
>in my opinion the number of disks in the whole array that makes a
>difference. I know that (some) IBM storages  (and maybe other vendors as
>well) have the ability to have e.g. 2 RAID 5 arrays acting as one
>towards the OS. I don't know if this is what you're talking about? We
>have talked to IBM about this for some time ago, but they didn't really
>recommended this solution.
>I can't remember the exact reason, but I think it was something like it
>didn't really gave any improvement of performance but in turn it added
>some unnecessary complexity to the setup.
>
>BTW: It was my understanding that LUNs was only relevant when talking
>about SCSI disks and not ATA/SATA disks, but apparently I'm wrong?
>
>Regards
>Steen

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