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

Changing Swap

Vito Sarducci — Tue, 27 Nov 2001 21:29:54 GMT

I have the following swapinfo. I need to change my swap to 3.75gb instead of the current 3.5gb. How do I do this again? My brain is fried and im on overload?

Please advise?

# swapinfo
Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 1536000 148772 1387228 10% 0 - 1 /dev/vg00/lvol2
dev 2048000 144856 1903144 7% 0 - 1 /dev/vg00/lvswap2
reserve - 919096 -919096
memory 1171704 643264 528440 55%

Re: Changing Swap

Michael Tully — Tue, 27 Nov 2001 21:36:18 GMT

Hi,

You can easily do this by adding another
logical volume and placing swap on it.

# lvcreate -n lvswap3 /dev/vg00
# lvextend -L 256 /dev/vg00/lvswap3
# swapon /dev/vg00/lvswap3

Edit your /etc/fstab file and add the
following entry.

/dev/vg00/lvswap3 ... swap pri=1 0 0

HTH
-Michael

Re: Changing Swap

Craig Rants — Tue, 27 Nov 2001 21:37:47 GMT

Vito,
This is from an HP LVM doc.

IX) How to increase the primary swap

Note: Because of the contiguous allocation policy, create a bigger
logical volume and modify the Boot Data Reserved Area (BDRA) to make it
primary.

1) lvcreate -C y -L 240 /dev/vg00
The name of this new logical volume will be displayed on the
screen, note it, it will be needed later. (let say it
is /dev/vg00/lvol8)
Note: This new logical volume has to be in vg00
2) lvlnboot -v /dev/vg00
This will display the current root and swap volumes
Note: lvol2 is the default primary swap.
3) lvlnboot -s /dev/vg00/lvol8 /dev/vg00
Note: use the logical volume name from step 1
4) lvlnboot -R /dev/vg00
Recover any missing links to all of the logical volumes specified
in the BDRA and update the BDRA of each bootable physical volume in
the volume group
5) reboot the system

Hope this helps,
C

Re: Changing Swap

Deshpande Prashant — Tue, 27 Nov 2001 21:48:37 GMT

Hi
If you have additional space, create another swap volume of required size and enable swap on it.
Remove the entry for existing swap (lvswap3) from /etc/fstab and reboot the machine to reclaim the lvol.

Thanks.
Prashant.

Re: Changing Swap

Bernie Vande Griend — Tue, 27 Nov 2001 21:51:28 GMT

Michael's directions are correct. (although you can create the size and logical volume in 1 command: lvcreate -L 250 -n lvswap3 vg00)

If you don't want to add a third swap area and just want to expand the lvswap2 one, you will have to comment out the entry for lvswap2 in /etc/fstab and reboot. When the system comes back up, you can use lvextend to expand that logical volume (lvextend -L 2250 /dev/vg00/lvswap2) and then use swapon /dev/vg00/lvswap2
to add it back in. There is no way to remove a swap area without rebooting.

Re: Changing Swap

Sridhar Bhaskarla — Tue, 27 Nov 2001 22:05:29 GMT

Do not forget C y options while doing the lvcreate. Swap should be contiguous.

Morever you want to make sure the swap logical volume sizes are equal (not mandatory). So, I would say the preferred method is Craig's. During that process you would want to create two lvols of equal size and contiguous on different disks totalling to 3.75 GB having equal priority.

-Sri