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  • 1.  SQL Server Memory

    Posted Mar 05, 2013 07:38 AM

    Hello

    I have a SQL Server 2008 R2 SP1. The Server needs about 26GB of memory. This whole memory is only actively used for about 60 minutes a day. The rest of the day the server idles. As it is a SQL Server it allocates all of the momory upfront.

    The applications team told me, that they need this amount of memory to do their work. My virtulization heart says that this is momory wasting. Most of the time the momory could be used more efficent by other VMs.

    Are there any recommendatin to deal with that circumstance?

    Thanks for your feedback.

    Best Regards

    Dennis



  • 2.  RE: SQL Server Memory

    Posted Mar 05, 2013 10:29 AM

    I think saying they 'need' the memory is just part of being part of an applications person/team! There is some ego related issue for IT people and resources e.g. "I must not be a real man if my SQL server could function adequately with 8 GB RAM and 2 CPUs"

    I feel your pain, but as the infrastructure guy, you may be the one who has to reign in the teenagers!

    Best case scenario: reduce the RAM and closely monitor SQL performance. You may need to increase again if those 60 minutes prove to be a problem. My bet is that you can actually get away with much less RAM for the VM.

    Other ideas (which will induce swapping - so be careful) might include creating a Resource Pool with a limit of the amount of RAM you want to assign to the SQL Server, but allow the SQL to have the amount of RAM the dev's want.



  • 3.  RE: SQL Server Memory

    Posted Mar 05, 2013 10:49 AM

    Hi

    First of all thanks for your replay. Monitoring and testing has confirmed that the VM is really using the RAM in this 60 min. time slot. Reducing the RAM ends up in slower application performance. When I look at the "Memory | Guest Active (KB)" counter I can see that the value raises up to the configured memory.

    The idea of applying a limit to the VM came in my mind too. I will test that. My expectation is, that the VM will work with near the same performance as with lowe memory configured.

    Another possibility, which came to my mind, is to create a planned task and apply a RAM limit based on the time in conjunction with a second planned task to remove the limit just before the machine starts working.

    Best Regards

    Dennis



  • 4.  RE: SQL Server Memory

    Posted Mar 05, 2013 10:55 AM

    How about a schedules task: "Change resource pool or VM resource settings"?

    Allow the usage when warranted and limit it when not needed.