Multi-Instances

  • SQL Server 2000:

    How much overhead resources does each Instance consume ?

  • It will use all resources that it can and instances will negotiate to get what they can from each other a lot of the time. As far as overhead you will have the install drive space (forget the total and it is based on what al you install), and a minimum in most cases of I believe 32MB memory used by each to start, it is a good idea to set the dynamic allocation of memory max to be no higher than 1/(totalnumberofservers) of the total memory - 128 megs for the OS to limit the amount of resource changes between each instance. It is also better to have each instances database on a seperate drive/array and on a seperate controller to minimize hard drive contention in read and writes. You should also as a good practice have at least 1 processor for each instance (this is due to threading in NT) and try to setup each instance to use its own CPU(s) to get maximum CPU utilization without too many threads waiting. Also a good idea to have a seperate NIC to handle requests for a specific instance to minimize network bottlenecking, if a large number of requests.

    "Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)

  • So Antares,

    Thank you for your reply because we are currently evaluating an 8-way db server for a development environment. We will have 8 instances of Sql Server running on this machine. It has 16GB of Ram. Would you suggest setting each instance to only use one CPU? Even if the load will not be equal across all instances? Also, if the system has 16Gig of ram, do you know if all 16 gigs minus say 500 MB for OS, are available to Sql Server? Thanks for any help you may be able to provide.

  • Personally, I'd let the instances compete and then see what happens. SQL does a good job of managing itself, though I'm not sure how the instances will work with each other.

    Steve Jones

    steve@dkranch.net

  • OK, thanks. Does anyone know if on WIN2K, I can use all 16Gigs for Sql Server?

  • Shouldn't be an issue. SQL is usually designed further ahead than Windows for scale. Supposedly SQL 2000 is 64bit ready. Just waiting for Windows.

    Steve Jones

    steve@dkranch.net

  • Yeah I just heard something about Windows only allowing services to use 50% of the available system memory or something to that effect. Am I totally off base here?

  • Not at lower RAM. I have a server with 2GB and SQL uses 1.7GB

    Steve Jones

    steve@dkranch.net

  • quote:


    Personally, I'd let the instances compete and then see what happens. SQL does a good job of managing itself, though I'm not sure how the instances will work with each other.


    In regards to CPU I would say this is saf to do and if becomes a problem. At minimum I would try to let each instance touch at least 2 CPUs for parallel processing to be utilized.

    Also (I am sorry as I have not needed to do this) SQL can address the RAM but there you have to turn this ability on. Hopefully someone will post those details or you can check out some of the other threads.

    "Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)

  • You're not going to be able to use all 16G for SQL unless you run DataCenter. Win2k AS maxes out at 8G.

    Andy

  • Yes, thank you. We are planning on using Datacenter. I'll try scanning the other threads, but if someone has information off the top of their head on how to access all the RAM on the box like Antares has mentioned, that would be helpful. Thanks again everyone.

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