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To use all the swap space, swchunk may have to be adjusted.

ManojK_1
Valued Contributor

To use all the swap space, swchunk may have to be adjusted.

Hi,

While installing HP Unix 11.31 on rx6600, i have received the following message.

NOTE: Unable to set kernel tunable to account for all the swap space on the system. There may be some swap space which will not be usable on the final system and messages may appear on initial startup. In order to use all the swap space the kernel tunable swchunk may have to be adjusted upward post-install.

Server is having 48Gb Memory and i have configured 36Gb for swap.

How can i make sure that assigned full 36Gb swap can be used by OS if required.

What chanes has to be done if i want to use the 36Gb Swap space?

Current swchunk value is 2048.

Manoj K
Thanks and Regards,
Manoj K
8 REPLIES
stephen peng
Valued Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

check this doc out:
http://docs.hp.com/en/939/KCParms/KCparam.MaxSwapChunks.html
have not experienced 11iv3, and don't know whether maxswapchunks kernel parameter tunable, at least, you could create a smaller swap, and after you finish installing os, tune maxswapchunks of swchunk as you needed and larger swap.

regards
James R. Ferguson
Acclaimed Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

Hi:

The kernel tunable 'swchunk' is applicable to 11.31. I would suggest that you read the manpages in light of your configuration before adjusting it. Have a look at the manpages for 'swchunk(5)'.

Regards!

...JRF...

Prasanth V Aravind
Trusted Contributor

Re: To use all the swap space, swchunk may have to be adjusted.


Yes .. the limit is 32GB..

Gudluck
Prasanth
James R. Ferguson
Acclaimed Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

Hi (again):

> Yes .. the limit is 32GB..

That's *old* documentation (11.11 or earlier) that doesn't apply to 11.31. At 11.31, a 'swchunk' value of 2048 means that the maximum swap is 4096 TB !

Exactly how did you install? What does 'swapinfo -tam' look like.

Regards!

...JRF...
TTr
Honored Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

> While installing HP Unix 11.31

If you get this error while you are reading the source media and installing the OS on the boot disk, you can ignore it. There is nothing much you can do or adjust at this point, the OS installer is loading in-core. It is a bogus error.

If you get this error while the server is booting up then you need to look at adjusting the kernel parameters as needed.
ManojK_1
Valued Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

Hi All,

Please find the swapinfo output from the server after installation.

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 36864 0 36864 0% 0 - 1 /dev/vg00/lvol2
reserve - 1331 -1331
memory 46722 4636 42086 10%
total 83586 5967 77619 7% - 0 -

Hi TTr,

I have installed HP Unix 11.31 so many times but never noticed the mentioned mesaage before.

Thanks to all the support.
Thanks and Regards,
Manoj K
R.O.
Esteemed Contributor

Re: To use all the swap space, swchunk may have to be adjusted.

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 36864 0 36864 0% 0 - 1 /dev/vg00/lvol2

You have 36Gb configured and all this space is available to be used.

Regards,
"When you look into an abyss, the abyss also looks into you"
ManojK_1
Valued Contributor

Re: To use all the swap space, swchunk may have to be adjusted.


I am accepting TTR's opinion as given below and closing the thread.

"If you get this error while you are reading the source media and installing the OS on the boot disk, you can ignore it. There is nothing much you can do or adjust at this point, the OS installer is loading in-core. It is a bogus error."

Thanks and Regards,
Manoj K