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

[lars ebeling]

Hi,

>From hpux-meminfo you get the 95% = (Total-Free)/Total . When you start 
HP-UX memory is used for "swapping" (up to 75%) and that is included in 
(Total-Free). This is called pseudo-swap. This is controlled by the 
kernelparameter swapmem_on. By default it's on (=1).

Memory used by processes should be 16372 - 212 - 4770

29% of your memory is used for pseudo-swap.
30% of your swapdisk is used.

Everytime when a process is started space on you swapdisk is reserved, so 
that the process won't run out of swapspace when it's needed.

Total Available swap = Available memory + Available swapdevice
Total Used swap = Used memoryswap + Used deviceswap + Reserved deviceswap

More confused now???

Regards
Lars Ebeling

----- Original Message ----- 
From: <thomas.seglard.enata at cnp.fr>
To: <hobbit at hswn.dk>
Sent: Thursday, July 27, 2006 2:46 PM
Subject: Re: [hobbit] Important ! HP-UX and the memory utilisation


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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