devices file name

[Boris_31]

Hi!
I have some problem.
i have DS25(Tru64 5.x) connecting to EVA 5000,
on EVA i make snapclon of this system and i need mount this snapclon on second DS25.
When EVA create snapclon and present to host, i do
hwmgr -scan scsi; and i can see /dev/disk/dskXXc COMPAQ HSV110 (C)COMPAQ bus-4-targ-0-lun-3.
All work ok, but i cant make script because on ever snapclon i have dskXX+1 device.
How i can do static name for disk device ?

[Ivan Ferreira]

When you create the snapclone, you can manually set the WWID. The information I got is that if you set always the same WWN, you will always see the same device name, because device names are associated to WWN.

[Ivan Ferreira]

In case that you cannot get always the same device ID, you can set the OS unit ID, and you will see the Unit ID with hwmgr, for example:

hwmgr v d

79: /dev/disk/dsk4c COMPAQ HSV110 (C)COMPAQ IDENTIFIER=2202

use

hwmgr v d |grep "IDENTIFIER=2202" |awk '{print $2}'

[Johan Brusche]

Since dskXX was created at previous snapclone and does not exist anymore and not in use. You can use hwmgr to delete it and then use
dsfmgr -m dskXX+1 dskXX
or, if you do not delete it with hwmgr, you can use:
dsfmgr -e dskXX+1 dskXX

So you can reuse dskXX in your scripts.

Rgds,
Johan.

[Boris_31]

What is happend if i reboot system?
This device name change to dskXX+1 or no?
Can i reset this count to dsk1c w/o dsfmgr?

[Johan Brusche]

Boris,

The snapclone contains pointers to the original boot dsk-name in /etc/sysconfigtab "swapdevice" and in /etc/fdmns/* domain links. These should be modified to point to dskXX.

Johan.

[Ivan Ferreira]

Even if you remove the unused device with hwmgr, unless the device had the same WWN, will be detected as dskx+1. Once detected the device name is persistent across reboots.

[Boris_31]

How can i add device manually w/o hwmgr -scan scsi ?
Can i disable automatic discovery disk devices on reboot?

[Johan Brusche · Accepted solution]

Boris,

You cannot disable autodiscovery of new units at boot-time, nor should you add dsk's manually with mknod or MAKEDEV on V5.1x

But, please read the dsfmgr manpage... in particular the purpose of the "-I" switch, it brings the device instance number back to the lowest possible number.
This feature has been introduced to V5.1B with patchkit#1 and in V5.1A with patchkit#5 and was in high demand by customer just for those sites that use snap/clone regulary.

Rgds,
Johan.

[Boris_31]

Tnx, dsfmgr -v -I , reset device ID
But now i can't reset HWID on hwmgr :-)
my script:

hwmgr -delete -did 4
sleep 5
dsfmgr -v -I
sleep 3
hwmgr -scan scsi
sleep 3
mount -t advfs eva_domain#my_fs /clone