Any tips to grow iSCSI LUN

UNIX AIX
1

Hi,

I have an iSCSI LUN attached to an AIX 5.3 box. It's initial size is 250GB, I just grew it on the SAN to 300GB, but AIX is not seeing the change. Right now I have some processes going and it's eating up the disk space. I need to grow this lun by atleast 30GB otherwise the process with bomb and that will not be good. chvg -g <vgname> is not working. I'm thinking I need to varyoff, then varyon this disk in order to get it to work, but I can't afford that now.

If anyone has any tips and have successfully did this without take the fs offline, I would love to hear it.

2

Then something is seriously wrong. Given so few additional data i can only speculate and try to ask the right questions:

  • have you had a look in "errpt"? Is there anything relevant?

  • Did you try to let "cfgmgr" run? With which outcome?

  • Do you use the the LUN directly or over a VIOS? If the second option: have you the same effect as in the LPAR on the VIOS too? If the first option: which drivers do you use to access the disks (SDD, PCMSDD, ??) What are your relevant software releases?

  • Sometimes - very rarely - the ODM gets corrupted for no apparent reason. Did you try a "synclvodm" or something such?

I hope this helps.

bakunin

3

Yip. This is the last entry in the error report.

Date/Time: Wed Feb 9 11:54:46 EST 2011
Sequence Number: 15049
Machine Id: 00CDE13F4C00
Node Id: MurphyT
Class: H
Type: TEMP
Resource Name: hdisk3
Resource Class: disk
Resource Type: osdisk
Location:
VPD:
Manufacturer................LEFTHAND
Machine Type and Model......iSCSIDisk
ROS Level and ID............38353030
Serial Number...............00000000
Device Specific.(Z0)........000005323B001022
Device Specific.(Z1)........000000A8

Description
DISK OPERATION ERROR

Probable Causes
MEDIA
DASD DEVICE

User Causes
MEDIA DEFECTIVE

    Recommended Actions
    FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY
    PERFORM PROBLEM DETERMINATION PROCEDURES

Failure Causes
MEDIA
DISK DRIVE

    Recommended Actions
    FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY
    PERFORM PROBLEM DETERMINATION PROCEDURES

Yip. Came back with no errors

The LUN is used directly. The default iscsi drivers are being used (if that's what you mean).

I haven't tried it, can synclvodm be executed while the system is active?

Very much. Thanks!

4

Hello again, sorry for not answering earlier. It was easter holidays and i was vacationing abroad.

Did you check the technology level? AFAIR "chvg -g" came into AIX at some 5.3-TL, but i can't really remember which. You'll probably find that one easy enough, i suppose.

Yes, this is what i meant. I'm not sure if an iSCSI-connection and its drivers is/are able to propagate a LUN change to the AIX machine. Direct FC connections driven by SDD or PCM are able to do so, but that doesn't necessarily meant that the same is the case with iSCSI. Maybe what works over glass doesn't work over copper at all. We exclusively use FC connections, so i can't really help you there for lack of operating experience.

Have you tried a "bootinfo -s"? What does it report, the old or the new size? This should work regardless of the disk being in a VG or not, it questions the driver layer below the LVM.

I hope this helps.

bakunin

5

Bootinfo shows the old size.

bash-3.00# bootinfo -s hdisk3
256000

6

If all else fails you could always assign a new 300GB LUN to the VG, use migratepv to migrate from original disk to new and then you can take the original disk away (after doing reducevg of course).