Re: AIX Memory and Paging Space

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

  • Next message: Holger.VanKoll_at_SWISSCOM.COM: "resetting firmware-passwd on p550" 
    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
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        -----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: Holger.VanKoll_at_SWISSCOM.COM: "resetting firmware-passwd on p550"

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