problem with swap usage under Solaris

Dominique Frise Dominique.Frise at unil.ch
Tue Jun 19 16:44:31 CEST 2007


Hi Henrik,

I wrote about this issue several weeks ago and since I didn't get any answer, 
I assume it was not clear 
enough.(http://www.hobbitmon.com/hobbiton/2007/04/msg00119.html)

Let'me give a second try ;-)

We have several SAP servers under Solaris that are constantly over the swap 
warning threshold (50 %).
SAP application does indeed *reserve* a lot of swap that confuses hobbit.
In the following example the server has 32GB of RAM memory and 32GB of disk 
swap space.


Swap outputs
------------
# swap -s
total: 22347128k bytes allocated + 18080512k reserved = 40427640k used, 
13640896k available

# swap -l
swapfile             dev  swaplo blocks   free
/dev/md/dsk/d5      85,5      16 66341232 65799424


Hobbit memory col. display
--------------------------
         Memory              Used       Total  Percentage
&green  Physical          30460M      32768M         92%
&yellow Swap              39493M      52779M         74%


Top display
-----------
last pid: 14928;  load avg:  2.68,  2.37,  2.00;       up 8+05:24:38   16:22:04
479 processes: 476 sleeping, 3 on cpu
CPU states: 81.3% idle, 11.4% user,  7.3% kernel,  0.0% iowait,  0.0% swap
Memory: 32G phys mem, 966M free mem, 32G total swap, 31G free swap
...
...

Hobbit computes Used and Total using "swap -s" and this gives a percentage of 
74% where "top" tool only show ~ 3% (1/32)
Since version 3.6, "top" for Solaris uses output of swap -l for swap usage. 
(details under #24 of the faq at http://www.unixtop.org/faq.shtml#title6)

We think Hobbit memory display should also be based on *disk* swap only (output 
of swap -l)


Dominique
UNIL - University of Lausanne



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