Data files location.

Hello.
I have large database with very high workload (100 trans/sec avg.)
When database files were located on local disks on the server I tried to
part data files, index files, files with binary objects and log files from
each other and place them on separate physical discs to improve performance.
Now we're planning to use cluster server with external storage (HP MSA 1000).
A technician, who was configuring the hardware, told me that in this
configuration storage library segments presented to MSSQL server as discs are
already spread on many physical discs and there is no reason now to put
database files on different drives.
The question is: is this true? Will it be good if I'll put all files on
one logical disc and let storage library to manage data distridution across
physical discs?
Thanks.
Serge Shakhov
Hi
Ideally, the log and data portion of the database should be on different
LUNs ("storage library segments") and the Log should be on RAID-1 or RAID-10.
RAID-5 is not optimal for the Log due to it's high latency. Actually, with
the price of storage today, RAID-5 has no place near a IO intensive server.
Further to that, if you get presented 5 LUNs, and then present them to SQL
Server as only one disk, generally, you do not use up all the storage, so the
first 2 or 3 of the LUNS will have all the traffic, and there is no data on
the other LUNs, so they get no traffic. You don't want this. You rather have
5 database files, one on each LUN so that all the drives are busy.
Without knowing exactly how the LUNs are mapped to the physical drives and
how you want to map to LUNs to OS drives, I can't pass more comment.
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"Serge Shakhov" wrote:

> Hello.
> I have large database with very high workload (100 trans/sec avg.)
> When database files were located on local disks on the server I tried to
> part data files, index files, files with binary objects and log files from
> each other and place them on separate physical discs to improve performance.
> Now we're planning to use cluster server with external storage (HP MSA 1000).
> A technician, who was configuring the hardware, told me that in this
> configuration storage library segments presented to MSSQL server as discs are
> already spread on many physical discs and there is no reason now to put
> database files on different drives.
> The question is: is this true? Will it be good if I'll put all files on
> one logical disc and let storage library to manage data distridution across
> physical discs?
> Thanks.
> Serge Shakhov
|||Mike,
Is there a net guide somewhere on setting up log files and data optimally?
Thanks,
Mica
"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:F43766EE-6358-4515-B6A3-7705B516DA18@.microsoft.com...[vbcol=seagreen]
> Hi
> Ideally, the log and data portion of the database should be on different
> LUNs ("storage library segments") and the Log should be on RAID-1 or
> RAID-10.
> RAID-5 is not optimal for the Log due to it's high latency. Actually, with
> the price of storage today, RAID-5 has no place near a IO intensive
> server.
> Further to that, if you get presented 5 LUNs, and then present them to SQL
> Server as only one disk, generally, you do not use up all the storage, so
> the
> first 2 or 3 of the LUNS will have all the traffic, and there is no data
> on
> the other LUNs, so they get no traffic. You don't want this. You rather
> have
> 5 database files, one on each LUN so that all the drives are busy.
> Without knowing exactly how the LUNs are mapped to the physical drives and
> how you want to map to LUNs to OS drives, I can't pass more comment.
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
>
> "Serge Shakhov" wrote: