LVM vs VXVM questions

[Leslie Fischer]

We currently have several HP-UX 11.11 systems connected to an EVA6000. We have several packages that are in a HP MCSG Clusters using VxVM disk groups and LVM disk groups. We use SSSU scripts to bring down the packages, create Snapshots on the VxVm disk drives, and then mount the snapshots to another server for doing backups.

We are also using Veritas VVR to replicated the disk groups to a remote EVA4000. We have one package that uses a LVM disk group that does not get snapped and is not replicated to the remote site.

We are getting ready to migrate to HP's CA(EVA's Continuous Access) and then in the near future all the PA-RISC 11.11 will migrate to HP-UX 11.31, itanium servers.

We own LTU's for Online JFS, VxVM VolMgr, and VVR. VolMgr and VVR support is very costly and my management wants to drop support for VxVM Vol Mgr and VVR. I still want to be able to expand the filesystems on the fly. I know I need this for the LVM drives. But not sure about the Base VxVM and the ability to expand the filesystems on the fly without having VxVM Vol Mgr.

My questions:
1. After we migrate to CA can we discontinue using VxVM and convert all disks to use LVM disk groups?

2. Can we continue to do snapshots on the LVM drives and mount the snapshots on the other server for backups?

3. Will PVlinks do load balancing and/or automated failover between controllers on the EVA's?

4. Any gotchas, that anyone has experienced when using LVM's to do snapshots through SSSU scripts?

5. I have done a little reading on CLUI command set, does this replace SSSU or can you use either product to do snapshots?

Thanks,
Leslie

[Emil Velez]

You need to use what works best for your environment.

You have to umount the filesystem to extend it after extending the LV without online jfs. You are still able to extend the LV and FS it is just that you have to umount the FS without online JFS.

1. After we migrate to CA can we discontinue using VxVM and convert all disks to use LVM disk groups?

There is no automatic configuration to migrate from dG to VGs. There is a script to migrate from VGs to DGs. VXVM is neat in that way and many others.

2. Can we continue to do snapshots on the LVM drives and mount the snapshots on the other server for backups?

Snapshots are done via the disk array Business copy license not LVM.

3. Will PVlinks do load balancing and/or automated failover between controllers on the EVA's?

pvlinks do failover automated if there are multiple paths.

4. Any gotchas, that anyone has experienced when using LVM's to do snapshots through SSSU scripts?

The snapshots are done via the disk array not LVM. LVM does not know that there is a snapshot unless you present the snapshot or snapclone to the system. Which is s issue since the disks will have the same PVID and VGID.

5. I have done a little reading on CLUI command set, does this replace SSSU or can you use either product to do snapshots?

SSSU and command view are the utilities that control the EVA and create luns and snapshots on the eva..