vgexort/import EMC disks during 11i cold install

[Neil Truby]

Hi

I have several volume groups on EMC disks which i propose to import after a cold 11i install. The server is currently at 11.00 My question is will I have the same disk device files (dev/dsk/c10t10d4) at 11i that will match my map files created at 11:00 and if not how do you get around it?

MArtin

[Sridhar Bhaskarla · Accepted solution]

Hi Martin,

You can use either of these three ways.

1. Before cold installing, export the volume groups with -s option.

vgexport -v -s -m /tmp/vg??.map vg??

Repeat it for all the volume groups and copy the files to another server.

After cold install, import them using -s switch again. Copy the files back from the other server. Create directories under /dev and the minor numbers.

vgimport -v -s -m /tmp/vg??.map vg??

In this way, you don't need to specify the disks. System will scan and import them using the VGID in the map files.

2. Use -f option to capture the disks.

vgexport -v -f /tmp/vg??.disks -m /tmp/vg??.map vg??

Repeat it for all other volume groups and copy both the .map and .disks files to another server.

After cold install, copy these files back. Run ioscan -fnC disks and identify the disks. You just need to note the controller number (instance). For ex., c2 on 11.0 might have changed to c5. So, just replace all c2s with c5s in the disks file and then import after creating directories and mknods.

vgimport -v -f /tmp/vg??.disks -m /tmp/vg??.map vg??

3. Use the same export option as in 2. Note down the controller paths and the corresponding instance numbers. After installing 11i, run ioinit to change the instance numbers to that of 11.0. Look at ioinit man page.

Option 1 is easy. But I vote for option 2 as it preserves the PV order.

-Sri

[Stefan Farrelly]

You may get lucky and your device files will remain the same. Any upgrades weve done the device filenames are always different!

The vgimport will work fine as long as you note a couple of things;
1. your mapfile - which you have
2. how many emc devices in each VG
3. the names of the OLD emc device files

No 3. is the important one. The naming convention EMC uses will be the same from the old device files to new ones, eg;
/dev/dsk/c10t4d1, d2 ,d3, t5/d1, t5/d2 etc.
So when you see the new device files the first part may be different (c10 may now be c20) but the later part of the device filenames should be the same. Even if its not the pattern will be the same (eg d1,d2,d3 then a new t number then d1,d2 etc). So if you note carefully the old pattern of device filenames when you export you will see the same pattern when you go to import and as you know how many devices are in each VG you will be able to figure them out easily.

Keep a full ioscan -fknCdisk output and strings /etc/lvmtab output handy from when you exported and your import will be easy.

[Neil Truby]

Thnks for your replies and clarifying my options. I was worried a one vg has 41 disks and the ioscan output looked horrendous...

cheers
Martin