Lvextend with strict policy problem ?

[gigiz]

Hallo ,
I have problem with lvm and strict policy.
I have this scenario.
One Vg whith 7 disks full. (attach vgdisplay and lvdisplay)
I want extend my logical volume but i have 3 free disk that i have added at vg.
I need to say if :
for extend i Must have another 7 disk ?
Can i extend lvol with warkaround?

[Victor BERRIDGE]

Hi,

Yes you have striped on 7 disks, 7 disks have to be added....

as a workaround you couls try to move a logical volume elsewere (a new group with your new disks?) and use the freed space to try to extend...


Good luck

Victor

[Senthil Kumar .A_1 · Accepted solution]

Hi gigiz,

It is not possible to extend the LV, because it needs another 7 disks to be added.

But if it is a Itanium Box, I have a work around, which is a unsupported method as far as HP is concerned. You can use this method for unrgent purposes till, you are ready for purchasing the rest of hardisks. Please confirm it is a Itanium, I will give you the steps for the work around.

But, be aware, my method will defeat the purpose of data striping across disk,that is "IO performance".It can only solve the purpose of extending the size temperorily. Ofcourse you need to revert back, after the required number of disks are place in future.

Regards,
Senthil Kumar .A

[Steven E. Protter]

Shalom gigz,

Possible issues:

There are limits to how many pysical extents a volume group can have. Be default it spreads out available extents, allocating for the maximum number of disks a vg can have, 255.

This can lead to you not being able to utilize all the space on the disks. The workaround is to create the vg anew with the -p max_physical
parameter. Spreading available extents over less disks helps.

You don't need seven disks to extend the volume group. A volume group can be extended 1 disk at a time.

SEP

[Victor BERRIDGE]

Hi again,
Should I understand you have only 1 lv in this group?
So my previous workaround is of no use...

Let me think again...

[Victor BERRIDGE]

Well you could add the new disks to the group (or create a new...), create a new logical volume, move some subdirectory ( that will leave you a significant space freed...) from your striped logical volume and create with ln -s a link to the new file system


All the best
Victor

[Zeev Schultz]

By the way,your 7 disks are LUNs coming from where? Since the allocation policy is strict I don't think though you can extend on the storage dynamically. Also using some kind of offline storage like tapes may help if you back up your data and rebuild group according to your needs.

[Senthil Kumar .A_1]

Hi Gigiz,

What is your HPUX box, a PA-RISC or an Itanium.

please give the following output.

model
uname -a

If its an Itanium box, I will give you a work around(if interested).

Regards,
Senthil Kumar .A

[gigiz]

PARISC

[Senthil Kumar .A_1]

Hi,

Hard luck, If it were a Itanium box, I would have given a tricky procedure with a specific command only available on Itanium versions. anyway nevermind.

Regards,
Senthil Kumar .A

[Carlos Roberto Schimidt]

If you assign new disk for a new PVG group in /etc/lvmpvg?

You can create new pvg group and i think it will be possible you extend lv.

[gigiz]

ok