memory utilisation very high

[Syedfurquan]

Hello Experts,

Need your help. I am having one hp p4440 server running HP-UX 11.11. We are facing performance issue on this server.

O/P of swapinfo:

#swapinfo -tam
             Mb      Mb      Mb   PCT  START/      Mb
TYPE      AVAIL    USED    FREE  USED   LIMIT RESERVE  PRI  NAME
dev        4096       0    4096    0%       0       -    1  /dev/vg00/lvol2
dev       20000       0   20000    0%       0       -    1  /dev/vg00/lvol10
reserve       -    4529   -4529
memory    15756   14739    1017   94%
total     39852   19268   20584   48%       -       0    -

From swapinfo O/P  Physical memory utilisation is always more than 90% but swap utilisation is 0% why so?

#top
25h78System: ofdmprodTue Mar 27 13:02:37 2012
Load averages: 0.10, 0.09, 0.09
89 processes: 164 sleeping, 23 running, 2 zombies
Cpu states:
CPU   LOAD   USER   NICE    SYS   IDLE  BLOCK  SWAIT   INTR   SSYS
 0    0.09   2.0%   0.0%   0.0%  98.0%   0.0%   0.0%   0.0%   0.0%
 1    0.10   3.9%   0.0%   2.9%  93.1%   0.0%   0.0%   0.0%   0.0%
 2    0.12   3.9%   0.0%   0.0%  96.1%   0.0%   0.0%   0.0%   0.0%
 3    0.09   2.9%   0.0%   3.9%  93.1%   0.0%   0.0%   0.0%   0.0%
---   ----  -----  -----  -----  -----  -----  -----  -----  -----
avg   0.10   2.9%   0.0%   2.0%  95.1%   0.0%   0.0%   0.0%   0.0%
Memory: 4773960K (2826236K) real, 5163184K (3017292K) virtual, 2550156K free  Page# 1/7
CPU TTY    PID USERNAME PRI NI   SIZE    RES STATE    TIME %WCPU  %CPU COMMAND
   ?   27711 ofsa154 20 49700K 19472K sleep    8:46  9.14  9.13 ofsrm
   ?   24488 oracle   148 20  4003M   251M sleep  245:04  8.68  8.66 ora_j000_DWPRD
   ?   27716 oracle   156 20  3764M  9668K sleep   39:10  6.30  6.29 oracleDWPRD
 3   ?    9135 oracle   154 20  3762M  8708K sleep    3:07  1.61  1.60 oracleDWPRD
 3   ?    3093 oracle   148 20  3923M   154M sleep  165:38  1.48  1.48 ora_dbw0_DWPRD
 1   ?39 root152 20 13632K 13632K run47:42  0.88  0.88 vxfsd
 3   ?    2575 root152 20 56288K 22116K run67:40  0.26  0.26 opcmona
 3   ?    3095 oracle   148 20  3782M 22468K sleep  273:26  0.21  0.21 ora_lgwr_DWPRD
 3   ?    1991 root152 20 52308K  9648K run8:10  0.19  0.19 ovcd
 3   ?    1964 root-16 20 37776K 16828K run    129:55  0.18  0.18 midaemon
 0   ?    2429 root152 20 36788K  5892K run1:57  0.18  0.18 ovconfd
 3   ?    2004 root152 20 32968K  9036K run8:31  0.16  0.16 ovbbccb
 1   ?    2188 root152 20   109M 29848K run81:29  0.16  0.16 coda
 1   ?    2254 root152 20 25168K  4920K run1:07  0.12  0.12 vxsvc
 0   ?    2570 root152 20 32988K  4600K run18:18  0.12  0.12 opcacta
 3   ?    2574 root152 20 32532K  5244K run51:06  0.12  0.12 opcle
 1   ?    1279 root152 20 62344K  5760K run1:50  0.10  0.10 cimprovagt
 1   ?    2604 root152 20 61576K  7696K run11:09  0.09  0.09 agtrep
 0   ?548 root152 20  2300K   380K run5:57  0.08  0.08 syncer
 3   ?    2469 root152 20 34924K  6296K run1:58  0.08  0.08 opcmsga
 3   ?21 root147 20    32K    32K sleep    8:43  0.06  0.06 lvmkd
 1   ?    1219 root154 20  6928K  1324K sleep    1:55  0.06  0.06 mib2agt
 1   ?    1276 root152 20 39224K  7444K run0:02  0.06  0.06 cimserver
 3   ?    2018 root152 20  3972K  1116K run0:01  0.06  0.06 windu_registryd50
 1   ?19 root147 20    32K    32K sleep    8:48  0.06  0.06 lvmkd
 3   ?    1182 root154 20  3684K   492K sleep    4:23  0.05  0.05 sendmail:
 1   ?    3068 oracle   154 20  3763M 10564K sleep    3:23  0.05  0.05 ora_pmon_DWPRD
 3 pts/0  5043 root178 20  7060K  5076K run0:00  1.00  0.05 top
 2   ?    3097 oracle   148 20  3770M 17476K sleep   10:16  0.05  0.05 ora_ckpt_DWPRD
 1   ?24 root147 20    32K    32K sleep    8:46  0.04  0.04 lvmkd
 0   ?    3759 oracle   152 20 39320K  4420K run19:44  0.04  0.04 tnslsnr

Any help will be very much appreciated.

Regards

Syed

[Dennis Handly]

>swapinfo physical memory utilisation is always more than 90% but swap utilisation is 0% why so?

The system is using pseudo-swap instead of device swap.  (This is a good thing.)

Right now the system is idle, so your output doesn't tell us much.

[Syedfurquan]

Hi Dennis,

Thanks for the reply. How to check the physical memory utilisation? And when server will used Pseudo-swap and when device swap?

Thanks

[Dennis Handly]

>How to check the physical memory utilisation?

Use a tool like glance/gpm.

>And when server will used Pseudo-swap and when device swap?

Using pseudo-swap is good, device swap is bad.  The OS will always try to use the former.

[Emil Velez_2 · Accepted solution]

your memory utilization will always be high since any unused memory that is not being used for processes will be used for buffer cache (11.23 and below) or file cache (11.31).  This means that any unused memory speeds up your I/O.

When you do a swapinfo -t  you see no device swap being used.. That is good.. That means that all of the processes fit in memory plus you are using the rest of memory for a buffer cache.

The pseudo swap that is mentioned is just a way for the system to fully use its memory.

Normally when a process loads in memory it must reserve swap space.  If you have 8 GB of memory and 4 GB of swap this would only allow you to run 4GB of programs..  With pseudo swap we make the OS think we have 12 GB of swap space to reserve so we can run 12 GB of programs before we are out of swap.  The overall effect is we are able to use all of our memory even if we do not have as much swap space as we do memory.. Now a days many systems have terribytes of memory to run everything in memory but we do not need terribytes of swap space.

Hope this clears things up.

[Syedfurquan]

Hi Emil,

Thanks.!!!