| Dave Hague
From: Dave Hague
Sent: Wednesday, April 09, 1997 9:54 AM
To: 'John Miller'
Cc: 'Eric Betts'
Subject: A: RE: Any known problems with hard disk caching and MS SQL Server?
John,
--- The following is a reply from Eric Betts who authored the paper I
mentioned in my previous mail ---
I am not aware of any specific reasons why any of Digital's RAID controllers
would cause degradation in performance.
I don't know what type of controller you have, if it is a backplane type
controller (i.e. KZPSC, KZPAC, KZESC), the write/back cache is disabled by
default. This is the defualt because of the additional risk of data loss
with w/b cache in the event of a power loss. W/B cache can be enabled
using the RAID Controller "swxcrmgr.exe" utility. The default amount of
cache is 4MB. If you really think the contorller is the bottleneck, the
amount of cache can be increased to 32MB. These controllers can handle
2000+ i/o per second with the right disk. I've seen situations were
a EISA controller was fully saturated, but it is much more difficult to
saturate the PCI based controllers.
Before trying to propose a solution, I need to understand what leads
you to believe that the storage subsystem is the cause for poor performance.
When you mentioned 30 users with extremley slow processing, slow in
comparison to what? How are CPU(s), Memory, Network, and I/O being
utilized? What is your RAID configuration (RAID 0,1,5,JBOD)
What else is running on this server? What are your memory, proc cache
and max async io settings?
---------------------------------------------------------------------------------------------------------
As I mentioned in my previous mail and as Eric confirms we need to understand
more about your configuration to help solve the problem.
Please give me a call on + (44) 1734 204106 or e-mail me on [email protected]
regards,
Dave Hague
Software Partner Engineering.
----------------------------------------------------------------------------------------------------------
John,
Firstly, I would suggest looking at the following technical white paper if you have
not already seen it. It was written last year but it remains a useful document.
location:
------------
http://www.partners.digital.com/www-swdev/pages/Home/TECH/documents/WNT-papers.html
Paper.
---------
SQL server for Windows NT Configuration and Tunning for Digital Alphaservers
As to your specific problem, could you provide us with some further information:
Machine type: Alphaserver (4100 etc).
Type of Raid Controller: Is it backplane RAID array subsystem.
Array 210 or 230.
or complete RAID array subsystem (e.g
310/450).
details of the difference can be found on.
http:\\\www.storage.digital.com
regards,
Dave Hague
Software Partner Engineering
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From: "John H. Miller" <[email protected]>
To: [email protected]
Subject: Any known problems with hard disk caching and MS SQL Server?
Date: Mon, 7 Apr 1997 19:12:31 -0700
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I have a customer reporting performance problems with hardware caching
RAID disk controller on an Alpha Server running MS SQL Server. The
prospect read in the SQL 6.5 unleashed book that SQL is notorious for
not being able to handle hardware caching. It is a dedicated ALPHA
Database server with 512MB RAM and running NT 3.51 Service Pack 5 and
SQL 6.0 Service Pack 3. They are using Platinum SQL financial GL, AP,
AR and Cash Management. There are 30 users attached to the server.
They said it is extremely slow processing reports from the FRX package
and are considering Crystal Reports instead.
I'd like to know if there are there any known problems / performance
tips your group is aware of between MS SQL Server and Alpha Servers with
caching controllers?
John H. Miller
* [email protected]
SQL Server Specialist - Architectural Engineer - Great Lakes District
* Voice Mail: 800-231-0950 x8045 Home Office:
216-417-0055 Sky Page: 800-759-8888 PIN 4855128
* http://www.microsoft.com/sql
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