Backup/Physical of TrueUnix System Disk

[mike_695]

We tried cloning/duplicating TrueUnix 5.1B System Disk (RZ29B) by booting from VMS 7.3-1 CD ROM and doing VMS BACKUP/PHYSICAL to the same type of disk but the cloned disk did not boot (this ised to work for OSF Unix)?

Any idea/suggestion ?

TIA,
Mike

[Vladimir Fabecic]

This is a question for TRU64 forum. You can not duplicate TRU64 system disk using VMS.
If you want to duplicate system disk to another disk (on the same machine), you must do the following using TRU64:
1. Create partitions and ADVFS boot block using disklabel
2. Create ADVFS domains and file sets
3. Mount file systems (in /mnt) and do vdump and vrestore
4. Modify the /etc/fstab because domain names and fileset names are different than original
I have duplicated system disks many times on many old machines that did not have RAID controller. If you want detail instructions, say so.

[Uwe Zessin]

I did it on Tru64 V4 and it worked, but Tru64 Unix V5 uses a persistent binding method based on the identity of the disk. Another disk has a different serial number and when booting it will create a new disk name.

[mike_695]

Thanks Uwe;

Your explanation makes sense.

As I said, I was able to use VMS Backup/Physical to clone Unix system disks in the past.
That was a simple and reliable solution.

[Uwe Zessin]

Yes, that worked on Tru64 Unix V4, because the SCSI address was encoded in the device name- similar to OpenVMS's handling (DKA300, DKA400).

A problem comes up when you start using multiple fibre channel storage arrays. Their target ports get looked up through the simple name server in the fibre channel switch, but the order can change!

OpenVMS has 'fixed' this by requiring a number in a vendor-specific SCSI page of the LUN (the so-called identifier) which is set on the storage array. The fibre channel driver takes this value (e.g. 55) and puts a fixed string in front of it to generate a device name - "$1$DGA55:".

Tru64 Unix uses a different approach. It takes a 'serial number' from the LUN and uses it to detect multiple paths to the same data as well as mapping this value to a fixed device name. That way you can even pull a locally attached SCSI disk from one server, plug it in another one and it is still recognized under the same name!

The downside, as you have found out, is with boot support. But you are not alone, beleive me, I have once 'killed' a colleague's Tru64 Unix cluster by assigning new disk identities on a storage array, because I didn't knew better.

[Vladimir Fabecic]

Device naming in V5.X is making lots of problems, but not too big problems. I said that fstab must be modified. In case of device naming problems you can change value in /etc/fdmns or use dfsmgr to change device file name. Do not forget that you can also use "old stile" device naming in V5.X (except in cluster envirement). If you can boot in single user mode everything can be fixed.
Besides, why not using regular TRU64 tools. Everithing can be done and you do have to use same type of disk.

[Vladimir Fabecic]

Sorry. I wanted to say that you do not have to use same type of disk (you can use biger disk for example).

[Hein van den Heuvel]

This is indeed more of Tru64 question than VMS.

We also used to use BACK/PHYS to clone Tru64 disks, but that was in the OSF days.

We long ago switched to the unix native dd, and more often than not jus rebuild a fresh system disk and copy critial /etc files into place once running.
The dd would be a simple:
dd if=/dev/rdisk/dskXc of=/dev/rdisk/dskYc bs=1024k

By doing it on a uninx box you can readily change things like /etc/fstab or the links in /etc/fdmns/* to new devce names if needed.
Optionally you can olse whipe the device database on the target to make it rediscover the WWID and restart numbering the disks at dsk1 instead of picking up the names from the original. But details for that are best investigated in teh Tru64 docu and/or specific questions asked forum.

Also... for further detail help you may want to indicate a little more than 'did not boot'. Any specific errors? Last command issued?

Regards,
Hein.

[mike_695]

Thanks for the replies.

Bttape looks the way to go.