OS pages per second very high on database server

  • I have been getting these messages very frequently from our performance diagnostic tool:

    8/23/2008 10:14:17 AM, OS Paging (Per Second) on is Critical.

    SQL Server instance - The operating system is paging at 3146.24 pages/second.

    OS Paging (Per Second): Page fault rate for all processes on the SQL Server computer.

    It seems that the database server is under memory pressure, but any additional feedback on this would be appreciated.

    __________________________________________________________________________________
    SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
    Persisting SQL Server Index-Usage Statistics with MERGE[/url]
    Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]

  • What are the box specifics? Mem, CPU, Page File size, OS

    SQL 2005? 64bit?

    Any other applications running outside of normal Windows processes?

    Are you limiting memory to SQL? (I would suspect not... due to the result)

    Are you using AWE?

  • Sean Kohler (8/24/2008)


    What are the box specifics? Mem, CPU, Page File size, OS

    SQL 2005? 64bit?

    Any other applications running outside of normal Windows processes?

    Are you limiting memory to SQL? (I would suspect not... due to the result)

    Are you using AWE?

    Sorry, should have provided more info. Here it is:

    RAM: 15.5 GB

    CPU: Intel(R) Xeon(TM) MP CPU 2.70 GHz

    PageFile Size: how do I locate the page file?

    OS: Windows Server 2003 Enterprise Edition SP1

    SQL 2000 SP4

    32-bit

    This is a dedicated database server - no other user apps running.

    We are using AWE: we have locked the working set to 11.5 GB (we should probably increase that).

    __________________________________________________________________________________
    SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
    Persisting SQL Server Index-Usage Statistics with MERGE[/url]
    Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]

  • 1) >> We are using AWE: we have locked the working set to 11.5 GB (we should probably increase that).

    NO you shouldn't, not if you are already seeing paging. Increasing SQL memory can only make things worse, not better.

    2) in task manager, show additional columns Page Faults and PF Delta and find out what is causing the paging. I have seen WMI go out to lunch on a number of client's system and page like crazy.

    3) Just to make sure, have you set /PAE in your boot.ini file so AWE will actually work?

    4) check out the undocumented dbcc memorystatus and check for anomolies against the online article about that command.

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • You need to look at the type of paging to know if there is a problem.

    Running backups can cause paging as the OS allocates file system cache, and this is a common cause of paging on a SQL Server and not usually a cause or concern.

    In addition, a lot of paging does not mean that anything is actually being written into the page file. You really need to look at the paging read and write rates.

  • TheSQLGuru (8/25/2008)


    1) >> We are using AWE: we have locked the working set to 11.5 GB (we should probably increase that).

    NO you shouldn't, not if you are already seeing paging. Increasing SQL memory can only make things worse, not better.

    2) in task manager, show additional columns Page Faults and PF Delta and find out what is causing the paging. I have seen WMI go out to lunch on a number of client's system and page like crazy.

    3) Just to make sure, have you set /PAE in your boot.ini file so AWE will actually work?

    4) check out the undocumented dbcc memorystatus and check for anomolies against the online article about that command.

    1) I thought increasing SQL memory would cause less paging, not more, as long as the set value is a couple of GB below the RAM value.

    2) How do I do that?

    3) Yes, Physical Address Extension is enabled.

    4) Will do

    __________________________________________________________________________________
    SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
    Persisting SQL Server Index-Usage Statistics with MERGE[/url]
    Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]

  • Michael Valentine Jones (8/25/2008)


    You need to look at the type of paging to know if there is a problem.

    Running backups can cause paging as the OS allocates file system cache, and this is a common cause of paging on a SQL Server and not usually a cause or concern.

    In addition, a lot of paging does not mean that anything is actually being written into the page file. You really need to look at the paging read and write rates.

    Thanks, I will look at what kind of apps are running at the time.

    __________________________________________________________________________________
    SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
    Persisting SQL Server Index-Usage Statistics with MERGE[/url]
    Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]

  • Task manager: Processes tab: View menu: Select Columns

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • I am currently experiencing some issues as well. Attached is a view of task manager on the server.

    RAM: 3.25GB

    CPU: Intel Xeon 5150, 2.66GHz

    Windows Server 2006 Std Edition

    SQL Server 2005 Std Edition

    Getting a lot of OS disk time alerts and OS average disk queue length alerts. I have also attached our S and L drive info...we have most log and data files separated out.

  • checkai (1/30/2009)


    I am currently experiencing some issues as well. Attached is a view of task manager on the server.

    RAM: 3.25GB

    CPU: Intel Xeon 5150, 2.66GHz

    Windows Server 2006 Std Edition

    SQL Server 2005 Std Edition

    Getting a lot of OS disk time alerts and OS average disk queue length alerts. I have also attached our S and L drive info...we have most log and data files separated out.

    You did not give us nearly enough information to help you. But I will say that you don't have much ram, and only 1 cpu?? What is the underlying IO configuration? Single drive in server partioned in to 3? RAID/ SAN??

    If you have poor IO performance you can

    1) fix queries to be more efficient

    2) improve indexing strategy to reduce IO demands

    3) buy more RAM

    4) buy more / faster drives

    5) fix configuration problems with IO system if any

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

Viewing 10 posts - 1 through 9 (of 9 total)

You must be logged in to reply to this topic. Login to reply