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All the memory

  • June 18, 2018 at 11:32 pm

    #77368

    Comments posted to this topic are about the item All the memory

  • June 19, 2018 at 12:38 am

    #1994385

    Good question, thanks Steve

    ...

  • June 19, 2018 at 1:38 am

    #1994391

    Thanks, Steve. 
    If there is nothing else running is it a valid option to leave the defaults and let SQL Server and the OS decide? The SQL Server developers after all are experts at memory management.  I wonder if I am helping or hindering by changing max memory manually. It would be different if running multiple instances, of course.
    Gordon

  • June 19, 2018 at 2:29 am

    #1994395

    GDownie - Tuesday, June 19, 2018 1:38 AM

    Thanks, Steve. 
    If there is nothing else running is it a valid option to leave the defaults and let SQL Server and the OS decide? The SQL Server developers after all are experts at memory management.  I wonder if I am helping or hindering by changing max memory manually. It would be different if running multiple instances, of course.
    Gordon

    Never leave defaults, always at least set a maximum limit.
    SQL Developers are not experts at memory management, at least not in my experience, they will use what is available.
    Running multiple instances is different, each instance needs enough memory to function, but not hinder the other instances at full capacity.

    -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    This thing is addressing problems that dont exist. Its solution-ism at its worst. We are dumbing down machines that are inherently superior. - Gilfoyle

  • June 19, 2018 at 2:45 am

    #1994400

    I agree. Set a max, otherwise you don't know how far SQL Server will go. It tries to take as much as it can, though the OS has the ability to steal it back. That's a relatively slow process, though, so I'd set a max.

  • June 19, 2018 at 3:27 am

    #1994402

    Agreed, always set a max.

  • June 19, 2018 at 6:53 am

    #1994438

    Great Question.  However...
    Are these newer Recommendations for 2017??  According to the link I provide below, 10G should be left for OS.
    http://codingsight.com/understanding-the-importance-of-memory-setting-in-sql-server/

    Recommendations and best practices

    Let us now briefly look at the techniques to size the memory.

    1. 1 GB of memory reserved for Operating System
    2. 1 GB each for every 4 GB of RAM after the initial 4 GB, up to 16 GB of RAM
    3. 1 GB each for every 8 GB in more than 16 GB of RAM

  • June 19, 2018 at 7:07 am

    #1994443

    I'm with you, Budd. I would allocate 52 GB myself (1+3+48).

  • June 19, 2018 at 7:12 am

    #1994445

    When I say "The SQL Server developers" I do mean the MS staff who develop SQL Server itself. If they are not experts at memory management then we have a problem with the product that so many of us know and love (kinda). So them, as opposed to "SQL Server Developers" (like me) who make a living out of using it. And I certainly would not claim any expertise in memory management.. 🙂

  • June 19, 2018 at 7:40 am

    #1994452

    The developers at MS do not set this by default. They never have, not because they can't, but because they don't want to set this on a server where other processes might need to run.

  • June 19, 2018 at 1:56 pm

    #1994537

    Budd - Tuesday, June 19, 2018 6:53 AM

    Great Question.  However...
    Are these newer Recommendations for 2017??  According to the link I provide below, 10G should be left for OS.
    http://codingsight.com/understanding-the-importance-of-memory-setting-in-sql-server/

    Recommendations and best practices

    Let us now briefly look at the techniques to size the memory.

    1. 1 GB of memory reserved for Operating System
    2. 1 GB each for every 4 GB of RAM after the initial 4 GB, up to 16 GB of RAM
    3. 1 GB each for every 8 GB in more than 16 GB of RAM

    This formula tends to fall apart at higher levels of RAM. 
    I have 384 GB of memory in one of my production servers.  By this calculation, I should allocate 321 GB and leave 63 GB for everything else.  I have 370 allocated to SQL, and 14 allocated to everything else.

    Michael L John
    If you assassinate a DBA, would you pull a trigger?
    To properly post on a forum:
    http://www.sqlservercentral.com/articles/61537/

  • June 20, 2018 at 2:55 am

    #1994576

    Trying to explain this to a junior dba who believes he knows everything about everything.
    talk about an uphill battle - he believes that because the server only hosts one instance of SQL server, it can get all the memory.

    trying to convince him that the OS also needs memory is an exercise in futility

  • June 20, 2018 at 3:13 am

    #1994578

    Good question to start the week on.thanks, Steve

    ____________________________________________
    Space, the final frontier? not any more...
    All limits henceforth are self-imposed.
    “libera tute vulgaris ex”

  • June 26, 2018 at 2:09 am

    #1995232

    Question: why does Windows want / need more free space for itself on systems with more RAM than on systems with lesser?

    The "core" of Windows should need the same amount and when there runs nothing else than the SQL Server service (and once per month Windows Updates), why should I waste 7 GB, while on a low-memory Systemn 4 GB (or even 2 on a very small machine) are enough?

    God is real, unless declared integer.

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