Importing disks and VxVM v 3.1

In VxVM v 3.1 and newer, can I import disks in a disk group that contain a point-in-time bit-by-bit copy, including all metadata, into a NEW disk group on the SAME server. Or, will Veritas bark that the disk is already in another disk group because the private region from the source was copied? With HP-UX LVM, the program vgchgid was used to change this metadata, specifically the vgid and pvid in the PVRA area for BCV EMC split disks. Is this possible with Veritas? Thanks.

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Ted, the following was taken from the EMC Manual "Veritas Toolkit for TimeFinder" which details the procedure to solve the problem.

Goal: How to import a Veritas BCV disk group into the same host
Goal: How to mount BCV copy of a Veritas disk group into the same host

Fact: EMC SW: TimeFinder
Fact: Application SW: Veritas Volume Manager (VxVM)
Fact: Application SW: EMC Foundation Suite by Veritas

Cause: Veritas Volume Manager writes a unique diskid to each disk. When the BCV copy is split and imported onto the same host, a situation may arise where Veritas Volume Manager selects the wrong disk when importing a disk group as duplicate diskid's exist. The procedure below ensures that the diskid on the BCV is different from the diskid on the STD copy.

Fix: The recommended method for importing a BCV disk group into the same host is to use the Veritas Toolkit for TimeFinder (VxTF), which is a component of EMC Foundation Suite by Veritas.

Fix: The procedure below should only be used if VxTF is not available on the host.

VERY IMPORTANT: Before implementing this procedure, the customer must be made aware that there is a window of vulnerability between the time the BCV disks are split and reinitialized (Step 3). In a worst case scenario, this may result in data corruption. If the customer is not willing to accept this risk, then VxTF should be the only suggested solution.

All steps are to be repeated each time the BCV copy is established:

1. Make sure the BCV disk group is deported: vxdg deport

2. Get a fresh copy of the STD disk group map file for use in step#7: vxprint -hvmps -g > mapfile

3. For each BCV (cXtXdX) device, immediately after the split: vxdisk -f init puboffset=X publen=Y privoffset=V privlen=W (repeat for all disks in disk group)

Obtain the correct offset information by doing a "vxdisk list" on the corresponding STD device.

4. Initialize the BCV disk group with at least one disk. The correct name must be given to each disk (e.g. disk01): vxdg init disk01=

5. Add each disk, one at a time: vxdg -g adddisk disk02= repeat for all disks in the disk group, and take care to associate each bcv device with the correct disk name

6. When all disks are added, make sure that all disks are present: vxdisk -g list.

The correct BCV disks must be present, and they must have the same names as in the STD disk group.

7. Using the mapfile, create the subdisks, plexes and volumes: vxmake -g -d mapfile

8. And start each volume (this example force starts the volume). vxvol -g -f start

Note: Mirrored volumes will be checked with a read-writeback sync when the volume is started. This may take some time, depending on the size of the volume.

9. Create the mount points and mount the file systems."


This was first published in April 2001

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