Server Change same old SAN......how to....

[harmt01]

I’m looking for the procedures for importing volume groups manually. This would be used in a situation where a server is being replaced.
A new server installed, a new OS is loaded and or ignited, and the LVM information is lost. The data on the disk array is still intact; however, the system is not recognizing the volume groups and LVM configuration.

I’m looking for the steps that need to be followed & what info I need to get off the old system.

I also am wondering will I come out with the same hardware numbers as I had before.

I have some info on this subject but I want an expert’s opinion please.

Thanks to all you guys and gals for your help!

Manual import:

1. Print out the group.dat file for this server.

2. Copy the mapfiles for this server. DO NOT copy over the vg00.mapfile.

3. If /dev/vgXX directories exist, rename them to /dev/vgXX.old (NOT vg00)

4. Create new directories for each volume group:

# mkdir vg02
# mkdir vg03 etc.

5. Create new group files for each volume group. Use printout of group.dat to get the correct minor number (0x00000)

mknod /dev/vgXX/group c 64 0x0?0000

where vgXX name of volume group
0x0?0000 minor number from group.dat listing

# mknod /dev/vg02/group c 64 0x020000
# mknod /dev/vg08/group c 64 0x010000

[Tim Nelson · Accepted solution]

As you did not mention what type of array the below is very generic.

1) make note of what HW addresses are related to which VGs

2) Present disk to new server ( same lun numbers makes it easier)

3) mkdir and mknod each /dev/vgxx ( the minor numbers on the group file make not a difference, as long as they are unique)

4) vgimport -m mapfile /dev/vgxx
( if you do not specify the device names I understand the the vgimport will search for them )

5) vgchange -a y /dev/vgxx

6) fsck if needed then mount using your saved fstab info.


That should be it.

[Sandman!]

Your steps look good and after step 5 import the mapfiles into the respective VGs. The hardware numbers i.e. c#t#d# may change but using vgimport(1M) with the "-m " option makes that unneccessary:

6. Import lvols into the VGs with the mapfiles that were copied over in step 2:

# vgimport -v -m " /dev/vg??

~cheers

[harmt01]

It's an MSA-1500 two controllers, 14 disk, but does it make a difference as long as it is the old one from the old system?

[Sandy Chen]

Hi,

The hardware numbers could be different, depends on where you put your HBA on= the server and the i/o path of each server is also different.

Your step is correct, step no 6. would be importing the VG from the mapfile on the new server.

Good Luck!

Regards,
Sandy