new volume group with service guard

[Quin Hammes]

We have a client who has an existing service guard cluster running (2 L2000s and a N). They are using an EMC Clariion and are getting a EMC Symmetrix. They would like to migrate the data in the cluster to the new EMC box. What is the best way to moving a cluster to use another volume group? Just edit all the config files and do a cmapplyconf? Or should we just migrate the data to the new volume group and then delete the old one and them rename the exisitng volume group (can you rename an volume group). Any advice would be appreciated and rewarded with points.

Thanks again,
Quin

[Sanjay_6 · Accepted solution]

Hi Quin,

I think what you should do is once you have added the hardware. Create a new vg on this, Copy everything from the old VG, export the new vg, export the old Vg and import the new vg with the old vg name. Make modifications to the lvmpvg if required.

Hope this points in the right direction.

Thanks

[Sanjay_6]

Hi,

I forgot to mention, replicate the new vg map to other nodes where this vg will be activated.

Thanks

[linuxfan]

Hi Quin,

Well the answer is "It depends". Ofcourse you can achieve this in various ways.

1. If the logical disk size in the symmetrix is the same as the Clarion, you could just add the new disks to the existing VGs and then pvmove the data and then reduce the current disks on the Clarion from the VG. You then may have to export the map files for the VGs to other nodes in the cluster. You may then have to rebuild the MC-SG cluster depending on what is defined as you cluster lock.

2. The second option is to create new VGs on the new disks and create new filesystems and mount them at temporary mount points and copy the data from the existing filesystems to the new ones. Reconfigure the MC-SG if necessary to indicate the new VGs/cluster lock disk and
remove the old VGs from the system.

You can rename a VG but you would have to export a VG and then import the disks beloging to that VG with a new name.

Are you looking for the exact procedure?

-Ramesh

[James R. Ferguson]

Hi Quin:

I see two possibilities. You don't specify how much or how you are going to actually move the data, but one way or another you are going to have to copy it to your new disk.

One way to achieve the objective is to create a new volume group (name and number), populate it with data, modify your package control scripts to point to it, and do a 'cmapplyconf'.

Another way is to 'vgexport' the existing volume group from the old disk array, create the same named (numbered) volume group on the new array, 'vgimport' it from the new array and populate it with data. In this case, no changes to your package control scripts should be needed.

My preference would be the second approach, since either way you have to move data. With the second method, no changes in the package control scripts need be done.

In either case, the key element is that the /etc/lvmtab file is updated with the correct device files.

Regards!

...JRF...