SQL server enterprise edition and the memory

  • Hi Guys,

    We are going to install the SQL server enterprise edition on Win 2003 advanced server with 4GB RAM.

    How should we divide the memory between the SQL server and operating system? and where do we do it? This server is going to handle nearly 200GB database.

    Regards,

    TK

  • You are pretty much limited with only 4GB RAM. Assuming the server to be primarily a database server, then the maximum RAM that SQL Server can use is 3 GB, and that is with the '/3GB' switch enabled in W3K and 'AWE' enabled on SQL 2K.

    Depending on whether the database will be mostly read, write or somewhere in-between will determine if more memory is required, so that both data and procedure cache sizes are optimal for your particular database server.

    Of course we shouldn't simply look at memory in isolation, but need to consider as well the number of CPUs, RAID/SAN configuration, etc.

  • This server has a QUAD 3.6 GHz processor with 6 drives (probably a setup of RAID 1 and 0) and yes, the data will be stored to SAN as well.

    I hope I answered the questions, please let me know if I havn't.

  • And yes, it will be clustered as well.

  • If it's just doing SQL Server work then give it the /3GB switch in boot.ini to let SQL use 3GB of RAM leaving 1GB for the OS.  If you have other processes on the box then you'll have to weigh it up.

  • Don't forget the following configuration options as well:

     exec sp_configure 'min server memory (MB)', 3072

     exec sp_configure 'max server memory (MB)', 3072

     exec sp_configure 'awe enabled' , 1

     exec sp_configure 'set working set size', 1

     go

     reconfigure with override

     go

     --

     -- reboot each side of the cluster after the configurations aer set

     --

    Also, you can use more than 3 Gb of RAM. You'll need the /PAE flag in the boot.ini file instead of the /3GB. However, PAE uses 1 GB of RAM itself to map additional RAM. It's suggested that you use this option only on servers with lots (12-16+ Gb) of RAM.

     

     

    RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."

  • Well I am working with the same issue these days. We had a 4GB server however now its 8GB and enabling AWE.

    I wont recommend /3GB switch in this case only because according to the authors of SQL Server 2000 unleashed by SAMS, one should leave about 50% of memory for the OS, stored procedures execution etc. By allowing SQL Server to access 3 GB and a big database you might endup cutting corners on performance.

    I would suggest to increase memory to 8 GB.

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