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Is the Page File a 'legacy' Safety Net? RRS feed

  • Question

  • Scenario:

     A computer has 4GB or more RAM installed.

     It also has 512MB or more of dedicated video memory.


     Processes like Windows Update and programs such as the

     Defragmenter, appear to work properly without on-disk

     Virtual memory.


     If the above conditions were true, Why would a person

     ever want/need to use a page file?

     

     

    Thanks, all of you, for the replies and information.  10/31/10

    What has been relayed by forum members:

    If Windows must have it, the operating system will create a

    20 MB page file in the system partition.

    I've not read any account of operating system processes that

    absolutely fail (except for Memory Dumps) if a page file is

    not present. This is what I was hoping to learn.

     

    Based on some of the information posted here, I have formed the

    following conclusions:

    Several years ago there were third party RAM managers that made

    the impossible, become possible. Perhaps this is still true and

    users should be asking Microsoft to enhance the performance of

    memory management, keeping in step with modern computer architecture.

    Further, with the presence of cache memory integrated into hard

    drives, the comparatively large volume of useable RAM and graphics

    memory, and the operating system's ability to create a discreet

    20MB page file, disable the large VMM page file unless, or until,

    you get 'Low Resources' warning messages.

     

     

     

    • Edited by Broke_It Sunday, October 31, 2010 11:09 AM
    Thursday, September 2, 2010 7:26 AM

Answers

  • Your question is the answer. The OS is designed with it, likes to have it available, doesn't use it with sufficient hardware and complains if you disable it.

    It makes it more friendly to being installed on old hardware and new netbooks. Which it is.

    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:53 AM
    Thursday, September 2, 2010 11:16 AM
  •  Page files are often useful for processes that consume a lot of
    memory, as the page file allows sections of memory in the paged pools to
    be swapped out to disk if they are infrequently accessed. It may not be
    as useful on a system that is built primarily for gaming, but many other
    applications such as messaging applications and  database applications
    benefit from having a page file.
     

    -- Mike Burr
    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:53 AM
    Thursday, September 2, 2010 3:16 PM
  • The following article can help you to understand Pagefile.

    What is the Page File for anyway? 


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”
    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:55 AM
    Monday, September 6, 2010 9:55 AM

All replies

  • Your question is the answer. The OS is designed with it, likes to have it available, doesn't use it with sufficient hardware and complains if you disable it.

    It makes it more friendly to being installed on old hardware and new netbooks. Which it is.

    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:53 AM
    Thursday, September 2, 2010 11:16 AM
  •  Page files are often useful for processes that consume a lot of
    memory, as the page file allows sections of memory in the paged pools to
    be swapped out to disk if they are infrequently accessed. It may not be
    as useful on a system that is built primarily for gaming, but many other
    applications such as messaging applications and  database applications
    benefit from having a page file.
     

    -- Mike Burr
    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:53 AM
    Thursday, September 2, 2010 3:16 PM
  • The following article can help you to understand Pagefile.

    What is the Page File for anyway? 


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”
    • Marked as answer by Arthur Xie Monday, September 6, 2010 9:55 AM
    Monday, September 6, 2010 9:55 AM
  • Just to add some ekstra stuff - I raised the question, seen from the server side, sometime back.
    http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2general/thread/b3ea9a47-ab95-49d4-80aa-3b7d24daf3f2

    As noted for Windows 7, you might want to read into the SuperFetch and ReadyBoost features..

    Tuesday, September 7, 2010 6:55 AM
  • Hi Jesper,

    The reference provided by Arthur seems to conclude that it is a change and monitor process with Server to tune the performance. (Last three paragraphs) I suppose that would apply to Windows 7 also. Although, most users would not have the technical knowledge to do so.

    Tuesday, September 7, 2010 9:58 AM
  • Hi Nano,

    Thanks for making the reply.

    As I read the referenced article it just states what is more or less commonly known to those that are interested in the page file. As people also comment in the referenced article there is lacking a Part 2 story.

    It still doesnt answer the original question - is it really needed to have a page file anymore. With memory being cheaper and widely more accessible, you want to place more and more into memory, rather than working on the disks. Especially on server side systems. The introduction of using the disk systems for memory is kinda like screwing up the different concepts, and is really more a remnant from the times where you had to use what you got, rather than building it specific.

    Also one argument is wrong, as far as I am aware:
    "If you think about it, the more memory you have, the less likely you are to need to page data out."

    This statement is wrong in the sense, that the operating system will page out items that are not being used, meaning that even with 2zillions of memory, playing solitaire, rebooting every month - would still generate a page file. The size would proberly be bigger with less memory, however it would still be there, it would still be using ressources on your OS and disk system..


    The short question would be:
    If I decide that I have enough memory, can I then remove the page file? - should be a simple yes or no..

    Tuesday, September 7, 2010 11:00 AM
  • Hi Nano,

    Thanks for making the reply.

    .....

    It still doesnt answer the original question - is it really needed to have a page file anymore. With memory being cheaper and widely more accessible, you want to place more and more into memory, rather than working on the disks. Especially on server side systems. The introduction of using the disk systems for memory is kinda like screwing up the different concepts, and is really more a remnant from the times where you had to use what you got, rather than building it specific.

    Also one argument is wrong, as far as I am aware:
    "If you think about it, the more memory you have, the less likely you are to need to page data out."

    This statement is wrong in the sense, that the operating system will page out items that are not being used, meaning that even with 2zillions of memory, playing solitaire, rebooting every month - would still generate a page file. The size would proberly be bigger with less memory, however it would still be there, it would still be using ressources on your OS and disk system..


    The short question would be:
    If I decide that I have enough memory, can I then remove the page file? - should be a simple yes or no..

    Hi!

    I would like to point you toward an even better article on the subject:

    http://members.shaw.ca/bsanders/WindowsGeneralWeb/RAMVirtualMemoryPageFileEtc.htm

     

    And to answer the original question...

    Windows DOES NOT work with RAM-memory...

    Windows works with VIRTUAL MEMORY (though Virtual Memory Manager!) No matter how much Physical memory you have!

    The virtual memory is a mix of RAM and pagefile so you can not assign any software to "run i RAM" only..

    If you "disable" your pagefile, windows will create one as needed.. and you end up with even worse performance than if you had not disabeld the pagefile.

    The Myth of boosting performance by disabling the pagefile is created and kept alive by people who never understood the Virtual memory manager!

    And disabling the pagefile on a server should render in unemployment... Since among other the eventlog is depending on having a small pagefile on your Windowspartition... (so always keep a small fixed pagefile on some 100Mb on your C:-drive)

    And place a larger pagefile on an own partition on a sepatate drive.. With a 4kb clustersize...

    Windows portions out data to the pagefile in 4Kb portions.. And as todays harddrives have quite a large diskcache (16 to 34MB) most pagewrites end up in the disks Cache.. And then lateron transfered to the physical disk!

    So.. to end up... when ever you hear someone talk about disabling the pagefile.. STOP LISTENING... That someone has no clue as to how windows actually works... :)

     

    (Please Excuse my poor spelling, I Swedish!)

    Tuesday, September 7, 2010 1:20 PM
  • From reading that and discussing with a mate, my conclusion is:

    The page file is basically there to prevent a process from recieving a out of memory exeption.

    As every process gets a static amount of memory assigned, as per design, you could potentially run into the issue where simple too many processes are requesting more memory, than what physically is available.
    If there was no page file, this process would receive a out of memory exeption and die. - instead the OS allocates memory to a page file and starts to operate with that.


    I'd say the history around it is basically trying to give a unified way to access memory for programmers. - The Virtual memory manager.
    Then not understanding how to release the memory from the applikation, forced OS developers to find a way to "save" the system, rather than just killing it.
    Better understanding


    With the fear that Mr. Johnson will stop listening, I'd say:
    1: If your running a static system,
    2: of newer date,
    3: with enough memory,
    I dont see any reason why you shouldnt disable your page file - there I said it! :)

    Especially on virtual servers, I dont want my 25 virtual servers to all be paging back and forth to my SAN disks, proberly raping my NIC's before my disks are stalling. I want to limit disk activity as much as possible.


    For me a page file is now too much an unneccessary complexity, to be recommended by default.
    Obviously it can still be used, but should only be used when actually needed and not be default.


    PS: Thanks alot for the link, that is proberly the best description on the matter I have read so far!

    Wednesday, September 8, 2010 6:33 AM