Removing special files

[Lor]

On a server running HP-UX 11i, I have removed "unwanted" special files using "rmsf -a" command.
These special files were unwanted as I am using secure manager on a XP frame to limit access LUN access on HBA WWWN base.
End result achieved is now that "xpinfo" only reports LUNs that server can really use.
But
1) "ioscan -fC disk" still reports LUNs as CLAIMED. Why ?
At least, it should show a "NO_HARDWARE" status

Question : Without rebooting, what is the solution so that "ioscan" reflects real situation i.e it should not report these LUNS at all anymore.

What would you recommend ?

Thank you.

Hugues.

[Ian Dennison_1 · Accepted solution]

Hugues,

I do not think that you have the option of stopping these files being rediscovered. As you may already know, the XP512 produces these cXtYd0 files as possible controllers for future disks presented within their LUN Range.

If you really really want to hide these for whatever reason, do some LUN Masking at your Switch level (you may need an upgraded Firmware Version and additional License to do this on brocades).

Question: How much damage do these null disks REALLY do to your system?

Share and Enjoy, Ian

[Lor]

You're correct.

It's not a big deal except that it is unsual do look at ioscan output and to see that some of the disks are CLAIMED but not really true disk space available for storage.

Instead, I have to rely on "xpinfo -m" output to know which LUN is accessible or not to a host.
What I find disturbing is that a standard unix sys admin (me for instance), not taking attention that host is attached to a XP, might conclude that disks are missing or a fc is dead.

Also,I would like to have your comments on the following :

A side effect of such cXtYd0 special files is that comparing "xpinfo -i" output from 2 distinct SAN attached HP hosts show relevant CU:LDEV as if they were accessible by both nodes.

I have to rely on "xpinfo -m" to figure out that as a matter of fact it is a 0 size LUN from one of the node perspective i.e that host can not use it.

To summarize :
1) "ioscan" on both nodes show disk device "CLAIMED" but it is not really disk space server can use.
2) it is only with the help of both "xpinfo -i" and "xpinfo -m" that I can really be sure that a given CU:LDEV is not potentially shared.

Am i missing something ?

[Tom Danzig]

FYI, any device files such as /dev/dsk/c?tdd0 are not really disk, just placeholders. See the following below:
disk 43 1/4/0/0.8.0.17.0.4.0 sdisk CLAIMED DEVICE HP DISK-SUBSYSTEM
/dev/dsk/c7t4d0 /dev/rdsk/c7t4d0
disk 56 1/4/0/0.8.0.17.0.4.1 sdisk CLAIMED DEVICE HP OPEN-E
/dev/dsk/c7t4d1 /dev/rdsk/c7t4d1
disk 44 1/4/0/0.8.0.17.0.5.0 sdisk CLAIMED DEVICE HP DISK-SUBSYSTEM
/dev/dsk/c7t5d0 /dev/rdsk/c7t5d0

If they were not there, certain versions of HP-UX would not recognize a disk if a LUN was assigned non-sequentially (i.e. cXt4d2 assigned and cXt4d1 was not assigned to the host.

[MANOJ SRIVASTAVA]

After removing the files run a insf -e again to insure that device files are created again , this will removce the unwanted Luns , ofcuse the LUN's should be out of the server disk string.


Manoj Srivastava