topic swap issue. in Operating System - HP-UX

swap issue.

aruns_s — Mon, 17 Mar 2008 05:51:40 GMT

Hi,
I was getting following message in syslog and it is clear that swap is heavily utilized.
Deferred swap reservation failure pid: 10205

Although glance was showing swap and memory utilization as almost 100%, swapinfo -tam output gives a different picture.Is there any bug in swapinfo outputs.Please refer following outputs..
# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 20512 1723 18789 8% 0 - 1 /dev/vg00/lvol2
dev 8672 1719 6953 20% 0 - 1 /dev/vg01/lvswap1
dev 8672 1714 6958 20% 0 - 1 /dev/vg01/lvswap2
dev 8672 1717 6955 20% 0 - 1 /dev/vg01/lvswap3
reserve - 39655 -39655
memory 78529 75169 3360 96%
total 125057 121697 3360 97%

CPU Util S SR R | 49% 49% 49%
Disk Util F F |100% 100% 100%
Mem Util S SU UBB | 98% 98% 98%
Swap Util U UR R | 97% 97% 97%

Re: swap issue.

Jeeshan — Mon, 17 Mar 2008 05:58:01 GMT

did u set pseudo swap in your system?

check your kernel paramaeter and its value set like,

dbc_max_pct
dbc_min_pct
swapmem_on

Re: swap issue.

Sajjad Sahir — Mon, 17 Mar 2008 06:03:28 GMT

swapmem_on =1, it is a parmeter
ok
then i think it will be ok

Re: swap issue.

Yogeeraj_1 — Mon, 17 Mar 2008 06:10:41 GMT

hi,

How much RAM do you have?

You MUST have at least as much swap allocated, or one form or another, as you have RAM in the machine. According to your swapinfo output, you can fully utilize almost 120MB of RAM when you add together your device swap (40MB) and your "Pseudo-swap" (the memory line) approx. 78MB.

kind regards
yogeeraj

Re: swap issue.

aruns_s — Mon, 17 Mar 2008 06:25:30 GMT

Hi,

Pseudo swap is enabled. My question is although glance shoows 97% swap utilization, how did swapinfo -tam output shows much lesser utilization for swap space?

Swap Util U UR R | 97% 97% 97%

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 20512 1723 18789 8% 0 - 1 /dev/vg00/lvol2
dev 8672 1719 6953 20% 0 - 1 /dev/vg01/lvswap1
dev 8672 1714 6958 20% 0 - 1 /dev/vg01/lvswap2
dev 8672 1717 6955 20% 0 - 1 /dev/vg01/lvswap3

Re: swap issue.

Jeeshan — Mon, 17 Mar 2008 06:38:23 GMT

>>Swap Util U UR R | 97% 97% 97%

the output shows first % is Current then Average then High

the values are not constant.

did u check your kernel parameters?

Re: swap issue.

Yogeeraj_1 — Mon, 17 Mar 2008 06:39:24 GMT

Hi again,

the figures do tally!
97% (glance) - 97% (swapinfo)

Below an extract from my system: 5% (glance) - 5%(swapinfo)

--------------------------------------------------------------------------------
CPU Util S SA | 8% 8% 8%
Disk Util V | 1% 1% 1%
Mem Util S SU UB B | 19% 19% 19%
Swap Util URR | 5% 5% 5%
--------------------------------------------------------------------------------

SRV2:>swapinfo -mat
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 512 0 512 0% 0 - 1 /dev/vg00/lvol2
dev 9728 0 9728 0% 0 - 0 /dev/vg01/swap01
reserve - 465 -465
memory 6310 351 5959 6%
total 16550 816 15734 5% - 0 -
SRV2:>

hope this helps!

kind regards
yogeeraj

Re: swap issue.

aruns_s — Mon, 17 Mar 2008 08:56:18 GMT

Hi All,

Please see the "FREE" field in my swapinfo output- what it has that much swap space free eventhough glance repots 100% utilization

Re: swap issue.

Don Morris_1 — Mon, 17 Mar 2008 09:39:39 GMT

And please note the "reserve" line in the swapinfo -atm output. You're out of swap reservation space, not actual disk blocks. Hence your devices show only some used -- but if you do the math [and the point to the total line is that it did the math for you], you'll find that (18789+6953+6958+6955)=39655. And when you add the reserved line, 39655 + (-39655) = 0. Hence your reservations remaining is completely a function of the free pseudo-swap (3360) and the 97% is entirely correct.

Re: swap issue.

Dennis Handly — Mon, 17 Mar 2008 15:18:07 GMT

>Deferred swap reservation failure pid: 10205

Do you know who 10205 is?
This process is evil and seems to have asked that swapspace not be charged until the page is touched. I'm not sure how this affects the swapinfo bookkeeping?

>ahsan: did you set pseudo swap in your system?

Of course, that's why the "memory" line shows up.

>Don: the point to the total line is that it did the math for you

Right, that's why if you don't want to strain your brain, you only look at the total line.