[hobbit] Important ! HP-UX and the memory utilisation

thomas.seglard.enata at cnp.fr thomas.seglard.enata at cnp.fr
Thu Jul 27 14:46:07 CEST 2006


Hello,

Thanks for your explanation ! I'm sorry to insist but it's a bit hard to 
understand. I think the true problem is the "reserved" memory. It's a 
maximum value and may not be used totally. For me, the real information is on the first line and given by the swapdisk. In my example, I got a total of 24G for swapping (also called paging by HP) and only 23% is used. 
Moreover, to determine the total physical memory used, a little script 
called "hpux_memory" is launched. I got very different results between 
this script and "swapinfo -Mm" :

bash-3.00$ ./hpux-meminfo 
Total:16372
Free:212

So, on my hobbit display I got percentage of memory utilisation > 95% 
whereas I got 29% with the other command !! Where is the truth ?!

bash-3.00$ /usr/sbin/swapinfo -Mm
            Mb         Mb         Mb        PCT
TYPE      AVAIL    USED    FREE  USED
memory  16372   4770     11602     29%

For the swap or paging memory, "swapinfo -dm" :

bash-3.00$ /usr/sbin/swapinfo -dm
             Mb      Mb      Mb   PCT              Mb
TYPE      AVAIL    USED    FREE  USED   START RESERVE  PRI  NAME
dev       24000    7264   16736   30%       0       -    1 /dev/vg00/lvol2

I got several servers with two or more swapdisks, so this command may be 
launched :

psu106:/# /usr/sbin/swapinfo -dtm
             Mb      Mb      Mb   PCT              Mb
TYPE      AVAIL    USED    FREE  USED   START RESERVE  PRI  NAME
dev        8192    4906    3286   60%      0            -    1 
/dev/vg00/lvol2
dev        8192    4908    3284   60%      0            -    1 
/dev/vg00/lvol3
dev        6144    5735     409   93%       0           -    0 
/dev/vg_swap/lv_swap01
total     22528   15549    6979   69%           -    0  -

If you can explain me where I'm wrong I would greatly appreciate ! Thanks again !
Sincerly,

Thomas

"lars ebeling" <lars.ebeling at leopg9.no-ip.org> a écrit sur 25/07/2006 
18:05:31 :

> 
> From: <thomas.seglard.enata at cnp.fr>
> To: <hobbit at hswn.dk>
> Sent: Tuesday, July 25, 2006 2:34 PM
> Subject: [hobbit] Important ! HP-UX and the memory utilisation
> 
> 
> > Hello,
> >
> > I got some troubles with HPUX and memory values. With Hobbit, in my 
memory
> > test, I got this :
> >
> > Memory              Used       Total  Percentage
> > Physical          16156M      16372M         98%
> > Swap              22117M      40372M         54%
> >
> > Everything seems normal but for me, these numbers are high 'cause this
> > server does nothing during the day. So, I connected to the server and ran
> > this command to see the available memory :
> >
> > psd216:~# swapinfo -atm
> >             Mb      Mb      Mb   PCT  START/      Mb
> > TYPE      AVAIL    USED    FREE  USED   LIMIT RESERVE  PRI  NAME
> > dev       24000    5474   18526   23%       0       -    1 
/dev/vg00/lvol2
> > reserve       -   11550  -11550
> > memory    16372    4754   11618   29%
> > total     40372   21778   18594   54%       -       0    -
> >
> > This output clearly shows an error in the Hobbit display. If you look, my
> > total swap memory is equal to 24000M not 40372M as shown in Hobbit and
> > only 23% is used !! Apparently, the values for the swap memory test 
are
> > taken from the last line and that's not correct !
> > Then I tried to execute the binary called "hpux-meminfo" in the client
> > "bin" directory and I get this :
> >
> 
> The 24000M is not swapmemory it is swapdisk, ie diskdevice configured to be 
> used for swap.
> 
> The 16372 is swapmemory or pseudo-swap as HP name it. It is a part of 
memory 
> that could be used used for swapping (or as I prefer paging). If you 
have a 
> lot of memory it is more efficient to use memory for paging. When a 
process 
> is started in HP-UX swapdisk is reserved for the process (reserve 
above). If 
> that swap isn't used, it's is waste of diskresources.
> 
> It is a try to explain.
> 
> Regards
> Lars Ebeling
> 
> 
> 
> To unsubscribe from the hobbit list, send an e-mail to
> hobbit-unsubscribe at hswn.dk
> 
> 



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