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Remove Alt links on lock disk

 
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Stuart Powell
Super Advisor

Remove Alt links on lock disk

I have a two node cluster that is running our production applications. I want to change the NODE_TIMEOUT setting. The cmgetconf command returns an error regarding differences in the volume group with the dual cluster lock disks. The node with that vg active has 18 physical devices. The /etc/lvmtab on the standby node has 20 physical devices. I belive the difference has to do with alternate links on the cluster lock disks. I've repeated the vgexport/vgimport steps.
1. How can I remove these without hosing the cluster while it is running? 2. Will this problem go away when the cluster is shutdown?
Sometimes the best answer is another question
10 REPLIES 10
David Bell_1
Honored Contributor

Re: Remove Alt links on lock disk

Stuart,

Can you verify this by doing a vgdisplay -v on the Volume Group associated to the lock disk. If it is indeed an alternate link, you should see it here. It will look similar to this:

PV Name /dev/dsk/c7t0d2
PV Name /dev/dsk/c11t0d2 Alternate Link
PV Name /dev/dsk/c15t0d2 Alternate Link
PV Name /dev/dsk/c19t0d2 Alternate Link
PV Status available
Total PE 9342
Free PE 0
Autoswitch On

If Autoswitch is on, you can remove the alternate link by performing a vgreduce on the primary link. The alternate should automatically take over. the line would be something like this:

vgreduce vg01 /dev/dsk/c7t0d2

HTH,

Dave
Christopher McCray_1
Honored Contributor

Re: Remove Alt links on lock disk

Hello,

Another alternative is to find the alternate links as they correspond on the active node and add them to the vg:

# vgextend vg?? /dev/dsk/c?t?d?


You should see the problem go away that way as well, and your alternate links will be available in case the primary path goes down.

Hope this helps

Chris
It wasn't me!!!!
Stuart Powell
Super Advisor

Re: Remove Alt links on lock disk

I don't want alternate links for the cluster lock disks. I don't think I can execute vgreduce on the node where the vg is NOT active.
Sometimes the best answer is another question
Christopher McCray_1
Honored Contributor

Re: Remove Alt links on lock disk

Hello,

When you did the vgexport/vgimport on the adoptive node, did you use the -s option w/ vgimport? If so, do not use that, instead, specify the disk, minus the alternate link, and you will have a 1-disk lvmtab entry.

Hope this helps

Chris
It wasn't me!!!!
Oleg Zieaev_1
Regular Advisor

Re: Remove Alt links on lock disk

Recreate map files using
vgexport -v -p -s -m vgXX.map /dev/vgXX
rcp map files to other node.
re-create vgXX:
vgexport vgXX
mkdir /dev/vgXX;mknod /dev/vgXX/group c 64 0xXX0000
vgimport -v -s -m vgXX.map /dev/vgXX

Should work.
Good luck.
Professionals will prevail ...
Stuart Powell
Super Advisor

Re: Remove Alt links on lock disk

Christopher,
I would do that but I have 18 physical volumes in that vg. Can I have 18 physical volumes in the command line?

Stuart
Sometimes the best answer is another question
Christopher McCray_1
Honored Contributor
Solution

Re: Remove Alt links on lock disk

Hello, again,

It is a very simple decision to make. Either you take my first suggestion and add the alternate links to the active volume group, which will solve your problem. Or, you try to vgimport by naming every single disk on the command line. I have ho Idea as to whether or not they will all fit on the command line because I don't have a volume group with that many disks yet and I always want to have my alternate links active. You could try listing the disks in a file and doing something like:

vgimport -v -m /tmp/vg??.map /dev/vg?? `cat diskfile`

Another possibility:

Find a time when you can fail the package over to the other node and vgreduce the alternate links out of the vg .


Hope this helps

Chris
It wasn't me!!!!
Stuart Powell
Super Advisor

Re: Remove Alt links on lock disk

Christopher,

You had the answer. I logged an HPRC call today, and the engineer responded with the same answer. I removed the volume group then ran the vgimport in a script with the list of 18 physcial device files. That eliminated the error messages I was getting from the cmgetconf. There are some warning messages, but I'm hoping those don't cause any problems.

Thanks,

Stuart
Sometimes the best answer is another question
Christopher McCray_1
Honored Contributor

Re: Remove Alt links on lock disk

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It wasn't me!!!!