Re: AIX Memory and Paging Space

Holger.VanKoll_at_SWISSCOM.COM
Date: 05/13/05

  • Next message: Yard, John: "Adding Expansion Unit to DS4300 Turbo"
    Date:         Fri, 13 May 2005 12:33:03 +0200
    To: aix-l@Princeton.EDU
    
    

    just one advantage and one disadvantage of a big "oversized" ps
     
    disadvantage: (cheap) diskspace wasted
    advantage: more time to react if an application starts to use much
    paging-space
    f.e. I prefer to have 4GB ps and get a warning when its 50% full (2gb
    used) than to have 2GB and get a warning when its 99/100% full
     
     
    >AIX will use the amount of memory solicited by your processes
    in rare cases processes demand real memory, they request the os to pin
    it (plock()). then, this statement is true for those processes.
    in all other cases processes demand only virtual memory and aix is free
    to put it in real mem or paging-space
     
     

    ________________________________

    From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On Behalf Of
    Green, Simon
    Sent: Friday, May 13, 2005 12:13 PM
    To: aix-l@Princeton.EDU
    Subject: Re: AIX Memory and Paging Space

    It's not possible to say that the paging space is oversized from the
    information available. If you allocate the minimum permitted paging
    space - required for the system to boot - but do no paging at all it
    will appear about 5% used. That's due to the LVM overhead and a small
    amount of data that goes in there at boot time.
     
    If the %used was 1% I might guess it was oversized; otherwise you'd have
    to know what the size really was. The original post does not suggest
    that this is the case.

    -- 
    Simon Green
    Altria ITSC Europe s.a.r.l.
    AIX-L Archive at https://new-lists.princeton.edu/listserv/aix-l.html
    New to AIX? http://publib-b.boulder.ibm.com/redbooks.nsf/portals/UNIX
     
    N.B. Unsolicited email from vendors will not be appreciated.
    Please post all follow-ups to the list.
            -----Original Message-----
            From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On
    Behalf Of hercom
            Sent: 13 May 2005 05:45
            To: aix-l@Princeton.EDU
            Subject: Re: AIX Memory and Paging Space
    	
    	
             
            Paging space use will be very low: 5% is about right--> A paging
    space so little used seems to be oversized. In general, the paging space
    should be under 40%, and the size must be determined accordingly to the
    application running (i.e. 4X the physical memory size for oracle). In
    AIX 5L a paging space can be reduced without rebooting. Anyway, AIX
    always uses some paging space, even keeping copies of the data on memory
    and on disk, as a "predictive" paging. 
             
    

  • Next message: Yard, John: "Adding Expansion Unit to DS4300 Turbo"

    Relevant Pages

    • Re: AIX Memory and Paging Space
      ... in rare cases processes demand real memory, they request the os to pin ... in all other cases processes demand only virtual memory and aix is free ... AIX Memory and Paging Space ...
      (AIX-L)
    • Re: Paging space on a fastT
      ... Concerning adding additional paging space to external disks, ... Depending on the version of AIX ... virtual memory in order to free up segments for other processes. ... that allocates virtual memory and real memory. ...
      (AIX-L)
    • Re: AIX Memory and Paging Space
      ... AIX will always try to use 100% of real memory--> AIX will use the amount of ... You can change the minimum and maximum amounts of memory used to cache files ... AIX Memory and Paging Space ... amount left unused for sudden demands). ...
      (AIX-L)
    • Re: PgSp and Paging Space
      ... memory that could be used for one process. ... Re: PgSp and Paging Space ... Now the IGES process runs until topas shows 1792 in the PgSp column, ...
      (AIX-L)
    • Re: PgSp and Paging Space
      ... represent a memory segment of 256M. ... Are you AIX 5.2 or greater? ... Subject: PgSp and Paging Space ...
      (AIX-L)