Memory error message on syslog

[Md. Khairul Alam Prodha_4]

Hi,

we have rx5670 HP-UX 11i v2, 8GB Memory server with 10GB swapspace with Oracle 9i(9.2.0.4.0)DB.

We are getting following error message on dmesg & syslog from 12:48PM to 16:45PM:
Deferred swap reservation failure pid: 4888
Deferred swap reservation failure pid: 4888
Deferred swap reservation failure pid: 7895

Could any one help why it is coming?
What is the solution?

Thanks

[Raj D.]

Hi Khairul,

Tou can check in glance if swap reserve space is being maintained. It seems like that you are going outof swap space and need more swap space.

In Glance "Swap Util" can be seen R R that is reserved swap space.

Check with :
# sar -v 5 5 ( and look for pi/po values , any non-zero value shows heavy swap activiy.)

also check :
# swapinfo -tm

hth,
Raj

[Sameer_Nirmal]

The errir shows that the processes with those IDs failed to run bacause system can't provide them the initial swap space required. The system is running out of swap space and can't allocate swap for those processes , hence it is being logged in dmesg and syslog.

Run swapinfo -tam and check the swap space utilization.

You would require to increase the swap space.
You need to configure a device for swap . Check if you have space available in vg00 ( preferred) or any other vg.
Decide the amount of more swap the system may require. Create a lvol using lvcreate -L
and add that lvol to system swap using swapon -a . You need to add the entry for the new lvol in /etc/fstab as well , so that the lvol would act as swap device after reboot.

[Raj D.]

Hi Khairul Alam,

You can add swap as follows, You have 8GB phy mem and only 10GB of swap. Addition of another 8GB of swap will give you good performance.

1. Create a lvol of 8GB with lvcreate .
# lvcreate -L 8000 -n swaplvol /dev/vgname
2. Try to avoid creating in the OS disk or same vg. Creating other vg and other disk will improve performacne.

3. Add entry on /etc/fstab

/dev/vgname/swaplvol ... swap pri=0 0 0

4. swapon -a
It will enable the device paging on /dev/vgname/swaplvol

And you can check the swap utilisation after this , with glance and vmstat , and swapinfo -tm

Hope this will help,

cheers,
Raj.

[Md. Khairul Alam Prodha_4]

Thanks for reply

We have following information:

# swapinfo -tm
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 10240 4387 5853 43% 0 - 1 /dev/vg00/lvol2
reserve - 5853 -5853
memory 8181 7761 420 95%
total 18421 18001 420 98% - 0 -
# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 10240 4387 5853 43% 0 - 1 /dev/vg00/lvol2
reserve - 5853 -5853
memory 8181 7692 489 94%
total 18421 17932 489 97% - 0 -
#
# swapinfo
Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 10485760 4492384 5993376 43% 0 - 1 /dev/vg00/lvol2
reserve - 5993376 -5993376
memory 8377224 7827036 550188 93%
#

Need we increase swap size?

[Sameer_Nirmal]

Yes you need to increase the swap space.
The system is already consumed 97% of current swap. As per processes requirement. system has reserved 5853MB swap space to make them run . Now system has only 489MB swap. If any new process requires to have more swap reservation to make it run on the system, system simply can't allocate that space to that process and will log the error in syslog and process won't run at all.

Adding more swap would resolve your swap issue but you are compromising the performance.

Your system is swapping heavily as it is using swap device at 43%. If you run vmstat -S 5 5 , you will see si and so number high. This is not good for good performance perspective. You need to increase the system RAM to get ride of this issue completly.