Adding disks to vg00

 
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Midrange
Occasional Advisor

Adding disks to vg00

Hi All

I have to extend /var/tmp online! there are no free extents available in the current volume group! I have two free 18Gb disks in the same cabinet, can I add these into vg00 and then extend /var/tmp "/var/tmp is a filesystem in its own right"

Please could someone advise the best way forward for this!

6 REPLIES 6
Karthik S S
Honored Contributor

Re: Adding disks to vg00

It depends how you configured vg00. Output of bdf will tell you whether /var/tmp is a filesystem or a normal directory (if it is a normal directory you would not see it it in bdf o/o unless ofcourse you have unmounted the filesystem).

-Karthik S S
For a list of all the ways technology has failed to improve the quality of life, please press three. - Alice Kahn
Mark Grant
Honored Contributor

Re: Adding disks to vg00

This is a perfectly acceptable thing to do. You can do it online if you have online JFS otherwise you are going to have to unmount it and that is probably going to be tough. If this is the case, you'll probably need to go single user.
Never preceed any demonstration with anything more predictive than "watch this"
G. Vrijhoeven
Honored Contributor

Re: Adding disks to vg00

Hi,

You can add both disks to vg00 and if online jfs is installed you can vgextend the lvols online ( You probebly need to do a lvchange -C n ( disable contigues allocation for the lvol) . Default /var/tmp is not a filesystm of its own. Use the bdf command to check, or do a mount or cat /etc/mnttab. If not you can add a new lvol in vg00, mount it /var/tmp2, mv /var/tmp /var/tmp2, umount /var/tmp2 and mount it on /var/tmp.

HTH,

Gideon
Midrange
Occasional Advisor

Re: Adding disks to vg00

/var/tmp is a seperate filesystem however I note that it was originally configured thus :-

LV Name /dev/vg00/lvol8
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 1112
Current LE 278
Allocated PE 556
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict
IO Timeout (Seconds) default

vg00 is currently mirrored and I will also have to mirror the 2 new disks.
This all means that /var/tmp will be split over 4 disks!

Please advise on best practise to achieve this, and whether the Strict allocation will cause an issue!
G. Vrijhoeven
Honored Contributor

Re: Adding disks to vg00

Hi,

To avoid /var/tmp to be on 4 disks you can create a 2 physical volume groups. When you configure it ( create tekst file in /etc/ named lvmpvg )check man lvmpvg, mind if possibile the controllers. So the mirror disks are on the second controller. \
Current disks e.g:
c1t0d6
c2t0d6

new
c1t0d5
c2t0d5

#lvmpvg:
VGNAME vg00
PVGNAME pvg01
c1tod6
c1t0d5
PVGNAME pvg02
c2t0d6
c3t0d5

To see if it works do a vgdisplay -v. The output must contain the pvgs

The Strict realocation policy ( default) can be overruled with the lvchange command. I thought is was lvchange -C y /dev/vg00/lvol8 but check it in the man pages, since i can not check it.

HTH,

Gideon
Trond Haugen
Honored Contributor
Solution

Re: Adding disks to vg00

You will need OnlineJFS in order to avoid taking the system down to increase the filesystem.
Once the two new disks are added to vg00 you can use pvmove to rearrange which disks the volumes reside on. Going for physical volume groups could be a good idea.
Yhe mirroring is done on volume (lvol) level.

Regards,
Trond
Regards,
Trond Haugen
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