add file system swap more than 4 gig

[Daniel_25]

Hi,

Just try to add new swap filesystem to 5120 meg on HP-ux 11.11.
It success (did via sam), and reboot,..
but when view via swapinfo -tam,
it just display that localfs swap FREE '1024' and LIMIT '1024'

weird, Is there some limitation (4Gig ??) for creating swap filesystem ?

Thxs

[Simon Hargrave]

The maximum swap size is determined by the kernel parameters maxswapchunks and swchunk.

Set maxswapchunks to the maximum size (16384), there is no disadvantage to this and it will let you add in future if you require. Assuming the default swchunk of 2048 this will allow up to 32Gb swap. The default value allows much less than this.

[Daniel_25]

maxswapchunks already 6049,
so I think the problem is not on kernel conf.

I tried several time and still no result.

But when I tried with value < 4000 meg, it 's ok , claim & view correctly via swapinfo

[Robert Bennett_3]

check your kernel parm maxswapchunks. The maximum swap space limit calculated in bytes is: (maxswapchunks * swchunk * DEV_BSIZE). We set maxswapchunks to 4096. We also never modify the kernel parm swchunk.

[Daniel_25]

already set maxswapchunk to max (16384)

try to add 5120 meg,..and still doesn't work

# 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
localfs 934 0 934 0% 1024 0 2 /home/paging
reserve - 1934 -1934
memory 6324 71 6253 1%
total 11354 2005 9349 18% - 0 -

[Greg Vaidman · Accepted solution]

Make sure you have PHCO_27007 or higher installed - your filesystem swap is working, there's just a bug in swapinfo!

If you go into SAM, it will correctly display your filesystem swap.

Regards,
Greg

[Greg Vaidman]

Just wanted to add a link to the patch, and an excerpt from the patch doc that describes the service request:
http://www2.itrc.hp.com/service/patch/patchDetail.do?BC=patch.breadcrumb.main|patch.breadcrumb.search|&patchid=PHCO_27007&context=hpux:800:11:11

( SR:8606364569 CR:JAGaf25208 )
swapinfo(1M) command reports incorrect values for the the configured filesystem swap space for values greater than 2 GB. This is happening because of overflow in storing the values greater than 2 GB in the data variables.

Resolution:
The code is modified to display correct data for values greater than 2 GB.