Adding LV to running package's VG possible?

[Ralph Grothe]

... I fear not, or at least not recommended.

The cirumstances are as such:
I have a running application as an SG package which I currently can't bring down.
On the other hand we are introducing overall monitoring by Tivoli.
Installing consultants and project's deadline are pressing to have this integrated while the customer doesn't even want their application being switched to a standby node :-(
So while the package was up (I know one shouldn't do this) I created in the package's shared VG a new LV and filesystem on it and mounted it under some mounpoint.
Then had the Tivoli agent/endpoint stuff installed (or copied) in this new Filesystem, and modified the package's control script in that way, that a new entry in the LV, FS, FS_MOUNT_OPT arrays been added and the customer_defined_(run|halt)_commands() functions got supplied with the necessary statements to bring the Tivoli stuff up or down.
I now want to distribute these modifications to the other cluster nodes, but fear that I will face complications on package halt or switch.
Is it at all possible to do what I want to do while the package is up?

[Sanjay_6 · Accepted solution]

Hi Ralph,

You can add a logical volume to an existing cluster vg/package without any downtime. Just add the logical volume to the vg on the node the package is active at that time, then to a "ll" on /dev/vg_name to find out the majot and minor device nos for that lv. recreate the device files with the same majot and minor nos on the other cluster nodes using mknod command.

Modify the package control script to mount the lv and then replicate this control script to other cluster nodes where this pacage is supposed to run.

However if you have to add a disk to the vg to do this, you'll have to shutdown the package, add the disk, do a vgexport on the node where you are adding the disk and then do a vgimport on the other nodes.

Hope this helps.

Regds

[melvyn burnard]

You should be able to do this without any issues.

[BFA6]

Hi,

I would not amend the package control files or config file with the package still up, this could lead to problems when trying to halt the package.

Again if adding a new logical volume I would recommend bringing the package down.

Regards,

Hilary

[Sanjay_6]

Hi Ralph,

Try this link below on how to add the lv to a sg vg,

http://support1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000058849485

Hope this helps.

Regds

[Rainer von Bongartz]

Ralph,

I think that this is not recommended but as far as I can see it should be of no problem.

Remember to vgexport/vgimport your VG and distubute the scripts.

Regards
Rainer

[PIYUSH D. PATEL]

Hi,

You can add the LV to the pakage's VG when the package is up. But after that you will have to distibute it and make required changes in the scripts using it.

Piyush

[MANOJ SRIVASTAVA]

Addding a lvol to a current running apckage will not invlove any downtime but then for it to function properly I would still test it during some maintenace window , this is bcoz the second mahcine should also sense the lvol and be good to mount it when the heartbeat goes down , in case it has some thing to do with a tivoli and jsut clooection data then you cans afely add it , howver if it ahs soemthing to do with real time production then I would suggest that you schedule some downtime.


Manoj Srivastava

[Ralph Grothe]

Thanks to all,

I know the steps involved to "sync" LVM and package configuration on all nodes (viz. vgexport, rcp, vgimport etc.) because I've done this some times before already.
But so far I've done this (to be on the safe side) only during a maintenance window and not with "hot" package.
Unfortunately this time circumstance don't allow this precaution.
That's why I just wanted to make sure if it was possible at all (though maybe not recommended).
And if I conclude from your answers correctly, you have confirmed this to me.

Regards
Ralph