Need Help on Veritas Volume Manager 4.1MP3

[gmathew]

Hi, I have Linux box(centos 4.7) with Sybase DB on it. The box has Veritas Volume manager 4.1MP3 and EMC SAN storage attached to it. All the Database file systems are configured using Veritas Volume Manager and is on the EMC SAN Storage. I would like to wipe out the existing operating system and reload centos 4.8. Is there a way to get back all the disk groups and the volumes along with the data that are on EMC SAN storage. Thanks in advance.

[g_lee]

If the data is completely on the EMC SAN storage (ie: no dependencies on the OS disk(s) at all), then you should be able to reinstall the new version of the OS on the OS disks (in principle anyway).

To get database filesystems and diskgroup back, reinstall Storage Foundation/VxVM once the OS (re)install is complete, then assuming the same disks are still visible to the server after the reinstall, you can import the diskgroup, start volumes and mount filesystems, etc as needed.

Obviously you would need to check the release notes and installation guide for your OS and VxVM version(s) for detailed steps and any specific issues/caveats/limitations, before going ahead.

[gmathew · Accepted solution]

Thanks Lee for the quick response. Yes, all the same SAN storage will still be visible for this box after loading the new OS. So effectively do I need to run vxdg deport command first and once the OS is installed, all I need to do is vxdg import? Also, Is there a way to take the backup of the existing VxVM configuration and once the new version of the OS has been installed, I can use the configuration to get back the vxvm configuration as it was earlier. Appreciate if you can share any doc or a link that I can refer too.

[Dev_Roy]

When you have reinstalled the OS, obviously the the DG will be in deported state, after installation of OS you just need to import the disk groups as usual as all the data and configuration information of the DG will be stored on the disk anyways.

If you wish to take backup of the DG configuration information then you can just keep the following direcotory stored somewhere else apart from OS disk.
/etc/vx/cbr/bk

The above directory holds the configuration information of all the DGs provided they were imported on that node at least once.
You do not need to take backup of the DG configuration as it will be anyways there on the disk header in a normal situation, if something has corrupted disk hearders then that is a different case.

Regards,
Dev

[g_lee]

gmathew,

What Dev has said above is correct; provided you have access to all the disks in the diskgroup (ie: as from before the reinstall), you don't actually need to recreate anything as it is stored in the dg info (ie: as long as you can import the diskgroup it will already be there, and you just need to mount it as it was on the old system)

That said, if you want to be cautious/conservative/paranoid, you can take a backup of the config directory as suggested; however it should not be needed (ie: if you're just reinstalling the OS and not touching anything else, the dg should be untouched so all the volume config should still  be there - if you can't import the dg and see the same volumes as before, this implies there's a problem eg: some disks may be missing, etc).

regards,
g_lee

[gmathew]

Thanks Lee and Dev for the pointer.  I will try this approach and see how it goes.

Really appreciate all the help extended by both of you.

Thanks.