SQL Server Performance

Pagefile size and location

Discussion in 'Performance Tuning for Hardware Configurations' started by agraaff, Nov 25, 2003.

  1. agraaff New Member

    I am installing a system with 4Gb Ram on Windows 2003 with SQL2000

    I have the following disk configuration:

    Disk0: Raid1 34Gb partition with OS

    Disk1: Raid1 29 GB partition with Application software (SAP) and 4Gb swapfile
    5 Gb partition and 4 Gb Swapfile

    Disk2: Raid1 34 Gb partition with SQL log file

    Disk3: Raid5 410 Gb partition with SQL Database


    The first question i have is:

    how does windows write to its pagefile, in Paralell (spread out the data over the x logfiles simultaniously to increase performance) or start at file 1 till its full and continue with the next?

    The next is:

    I can put all the pagefiles on a single disk (disk0 or disk1) is this a better option? this way i decrease the stress on or the OS or the Application (SAP)

  2. Luis Martin Moderator

    With Windows 2000, I was monitoring 2 swapfiles in differents disk.
    What I see is: Use 1rst swapfile until full and then use the second.
    I don't know how SAP stress server, if higth then is better to put swapfile in disk0.






    Luis Martin

    ...Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.
    Bertrand Russell
  3. satya Moderator

    Having a page file allows your computer's operating system to pretend that you have more RAM than you actually do. The least recently used files in RAM can be "swapped out" to your hard disk until they are needed later so that new files can be "swapped in" to RAM.

    One of the tips in this website refers:
    Assuming that SQL Server is located on a dedicated server, the location of the PAGEFILE.SYS is not critical. This is because SQL Server does not normally do any paging on its own. If you do notice that your SQL Server is paging regularly, then it needs to be tuned appropriately so that paging is virtually stopped. Generally, leave the PAGEFILE.SYS file on the same drive as the operating system.



    _________
    Satya SKJ
    Moderator
    SQL-Server-Performance.Com
  4. agraaff New Member

    SAP and SQL are both on the same server but i convinced the client to buy 2 extra disk to use for paging in RAID0.

    Arjan
  5. Luis Martin Moderator

    If I where you I use new disk to slip database and kip pagefile in SO.


    Luis Martin

    ...Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.
    Bertrand Russell
  6. satya Moderator

    Any chance of seperating SAP and SQL server on different machines?

    _________
    Satya SKJ
    Moderator
    SQL-Server-Performance.Com
  7. agraaff New Member

    The server is sized (not by me) to be able to handle both SAP and DB so we can't buy an new server now.

    Luis, you mean put the two extra disk with de DB-array and put the swapfiles on the OS disk?

    Arjan
  8. Luis Martin Moderator

    Yes, what I means is: If you have the chance to create a filegroup in new disk array and move some index, or some tables (most used) you will get more performace, and live swap in OS disk.



    Luis Martin

    ...Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.
    Bertrand Russell
  9. satya Moderator

    Have you collected any PERFMON stuff on this pagefile issue, if you do not have any issue then leave it as it is.

    _________
    Satya SKJ
    Moderator
    SQL-Server-Performance.Com

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