I would suggest that a test server with 256Mb RAM is woefully inadequate
for running MS Windows Server alone, let along putting a database
product on top. For our multi-user Windows implementations (we prefer
AIX but some customers request Windows) of our primary MRO (similar
requirements to your CRM applications I guess) application we have a
minimum spec of 4Gb RAM for running 2 Oracle instances and 2Gb RAM for
running one. For the number of connections you have (guessing here as I
do not know what your CRM application is doing) I would guess that your
best bet would be to build an Oracle instance using the "Transaction
Processing" template with 50% memory usage of a 2Gb RAM system.
MS Windows Server usually likes at least 350Mb to "do it's thing" and
any additional software/ windows options will increase this. Oracle on
top should be given at least 1Gb to play with although a minimum build
using 512Mb will work.
Even the laptop from which I am typing this email has 1Gb RAM with an
Oracle 10g instance using 512Mb of that for development purposes. As
memory is so cheap I suggest giving the application what it needs.
As for the shared/ dedicated server mode we find that dedicated works
well for us but from your description of your application it sounds as
if shared would be better for you. The description of shared is "Several
clients share a database-allocated pool of resources. Use this mode when
a large number of users need to connect to the database simultaneously
while efficiently using system resources".
One would normally expect a decent performance boost when moving from
SQL Server to Oracle but only on a decent spec server. On a poorly
specified server SQL Server may just have the edge in this case.
Also, your CRM application seems to be coded in an atypical manner by
creating so many concurrent connections. Perhaps you could look at that
as an area for tuning also.
I hope the above helps.
Regards
Garnet
-----Original Message-----
From: Claudio Alonso -Oracle DBA
[mailto:oracledba-ezmlmshield-x75661469.[Email address protected]
Sent: 30 January 2007 13:53
To: LazyDBA Discussion
Subject: Shared or dedicated server?
My client is a CRM application provider who usually installs their
application
running with MS SQL Server. This time thy have a client that is willing
to use
Oracle, so I'd believe the performance should be much better than usual,
but
it's not the case. They did their best without an Oracle DBA, following
external instructions from partners via email. The situation is kind of
critical right now because the performance is not good and the project
is in
danger, so they asked for my help.
So I'm starting to work with this database (Oracle running on a Windows
environment) behind a CRM application with 20/30 users. The application
usually opens 6 to 10 database connections for each user, so the amount
of
connections is normally about 200.
Most of the time the application is processing transactions, but it's
usual to
see several times a day big reports being run by the supervisors.
The performance is not good and the database is running on a 1 Gb RAM
Pentium
IV, configured to work with shared server processes (I believe it's a
mistake
though I don't have much experience in shared server mode so I might be
wrong).
Do you think that a database with these characteristics should be in a
P-IV
with 1 Gb of RAM running in shared server mode, or it would be better to
change it to a dedicated server environment (and/or may be add some
RAM).
At the same time, what is the minimal ammount of RAM that you recommend
for
such a thing? My customer's customer is about to run a test on a
separated
server, so I'm building a new environment from scratch. The additional
problem
is that the test server has only 256 Mb of RAM (is it me, or are they
shooting
to kill?).
I hope you can give me some advice.
Thanks in advance,
--Claudio
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