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AIX doing pgin's but has lots of memory

  • 1.  AIX doing pgin's but has lots of memory

    Posted Fri March 06, 2015 12:28 PM

    Originally posted by: mike_atcoitek


    We have an AIX 7.1 server. 

    We are getting some minor page in's according to topas / nmon statistics.  As many as 45000 in a 10s interval.

    However we have 131 GB of RAM and 128 GB of paging space. Of this only 17% of the RAM is computational and 81% is non-computational (file cache). But, according to topas 1% of our paging space is being used despite the fact we have 81% of our memory free (~94 GB).

    We have ~5 other servers and they all show "0% paging space used" and do not have pageins. 

    My question is why is AIX using paging space (and doing pagein's) when there is so much free memory.

    Right now I am thinking we configured something wrong and AIX is using paging space in its file cache when it could just use RAM.

    Hopefully I explain this clearly if you think you can help but need more details please let me know and I will provide them.


    #AIX-Forum


  • 2.  Re: AIX doing pgin's but has lots of memory

    Posted Fri March 06, 2015 12:30 PM

    Originally posted by: mike_atcoitek


    I am also going to dump our vmstat -v output as I think this may help:

    -bash-4.3$ vmstat -v
                 33554432 memory pages
                 32519872 lruable pages
                   518365 free pages
                        1 memory pools
                  4524014 pinned pages
                     90.0 maxpin percentage
                      3.0 minperm percentage
                     90.0 maxperm percentage
                     83.8 numperm percentage
                 27271953 file pages
                      0.0 compressed percentage
                        0 compressed pages
                     83.8 numclient percentage
                     90.0 maxclient percentage
                 27271953 client pages
                        0 remote pageouts scheduled
                     1147 pending disk I/Os blocked with no pbuf
                        0 paging space I/Os blocked with no psbuf
                     2228 filesystem I/Os blocked with no fsbuf
                      420 client filesystem I/Os blocked with no fsbuf
                   592003 external pager filesystem I/Os blocked with no fsbuf
                     17.2 percentage of memory used for computational pages
     

    #AIX-Forum


  • 3.  Re: AIX doing pgin's but has lots of memory

    Posted Fri March 06, 2015 10:35 PM

    Originally posted by: The_Doctor


    We have an AIX 7.1 server. 

    Yeah, but at what TL / SP level ?

    In any event, with no other info, my guess would be you have hit the problem fixed by APAR IV53587.

    http://www-01.ibm.com/support/docview.wss?uid=isg1IV53587

    If you're already at a service pack that includes IV53587, a call to IBM Support is probably in order.


    #AIX-Forum


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