topic Re: Swap Help in Operating System - HP-UX

Swap Help

Steven Chen_1 — Wed, 25 Sep 2002 14:41:51 GMT

Hello,

I have a new server with 4G swap on /vg00/lvol2. Two internal disks are going to be mirrored. I'd like to make the swap space upto 6G, but sam gives me error like these:

------------------------------
The command used to extend logical volumes, /sbin/lvextend, has
failed. The stderr output from the command is shown below. The
logical volume has not been extended.

lvextend: Not enough free physical extents available.
Logical volume "/dev/vg00/lvol2" could not be extended.
Failure possibly caused by contiguous allocation policy.
---------------------------

As noted, there is no advantage to add 2nd swap on the same disk. But how to add up the size of the primary swap?

Help will be greatly appreciated.

Steven

Re: Swap Help

Uday_S_Ankolekar — Wed, 25 Sep 2002 14:50:57 GMT

Unfortunetly you can not increase primary swap. You can create a secondary swap if you have physical disk space is available. It seems that you don't have free extentes to increase your logical volume.

Check with vgdisplay -v /dev/vg00 and see if there are any free pe's available. Or best way is if you have spare disk try to create secondary swap on that disk.

Goodluck,
-USA..

Re: Swap Help

Olivier ROBERT — Wed, 25 Sep 2002 15:05:55 GMT

Hi Steven,

You could not extend your swap space probably because of the contiguous allocation policy enforced on /dev/vg00/lvol2. This policy forbids the logical volume to be "fragmented" on the disk. lvol2 is probably "surrounded" by other logical volumes.
One (discouraged) solution would be to remove the contiguous allocation policy on the logical volume. The command is "lvchange -C n /dev/vg00/lvol2", but it's a bad idea, since it would have very bad performance issues.
Another solution is to create one additional 6GB swap volume on the same disk (with a contiguous allocation policy), designate it as the primary swap, and then remove the previous one. That will require a reboot. And don't forget to change the dump device to your new swap space (crashconf -r /dev/vg00/new_lvol) as you will probably remove your former swap volume, which is probably configured as the kernel crash dump device.
Regards,

Olivier

Re: Swap Help

S.K. Chan — Wed, 25 Sep 2002 15:23:45 GMT

Others have explained what the errors mean. My recommendation is leave the 4GB primary swap alone. Proceed with vg00 mirroring process. When you're done, add 2ndary swap, do not use vg00, use other VG (eg: vg01), (2GB then since you wanted 2GB), the "nice" thing is if you can, setup your 2ndary swap to be the same size as primary swap (same priority) so that swap interleave is enabled. BTW why do you need so much swap .. just keep in mind the memory swap ratio rule does not apply anymore nowadays.

Re: Swap Help

Thomas M. Williams_1 — Thu, 26 Sep 2002 12:04:38 GMT

I hope this helps. The text may a little sketchy b/c I pasted it.

#!/bin/ksh

# Defaults

PS3="Please select desired printer: "
fulllist="`cd /etc/lp/interface;ls`"

all_printers ()
{
# This is where your current syntax goes.
# Ex: hpnpadmin ${fulllist} If you can send all devices into the command ?

}

single_printer ()
{
select prtname in ALL Quit ${fulllist}
do
[ "${prtname}" = "Quit" ] && exit 0

if test -n "${prtname}"
then
if test "${prtname}" = "ALL"
then
prtlist="${fulllist}"
else
prtlist="${prtname}"
fi

break
fi
done

# Put the syntax for running the hpnpadmin
# Ex: hpnpadmin ${prtlist}
}

# Main

if test ${#} -ne 0
then
while getopts :s option
do
case ${option} in
s) select_on="Y" ;;
?) echo "Usage: ${0} [<-s>] (-s turns select option on)."
exit 4 ;;
esac
done
fi

[ "${select_on}" = 'N' ] && all_printers || select_printer

exit 0

Re: Swap Help

Olivier ROBERT — Thu, 26 Sep 2002 14:18:09 GMT

Hi Thomas,

That's a funny answer to our SWAP problem... :o)