AIX varyonvg fails hdlm volumes, "no good copies of the descriptor area".

Asset ID:	1-72-1012592.1
Update Date:	2011-10-18
Keywords:

Solution Type Problem Resolution Sure

Solution 1012592.1 : AIX varyonvg fails hdlm volumes, "no good copies of the descriptor area".

Applies to:

Sun Storage 9910 System
Sun Storage 9960 System
Sun Storage 9970 System
Sun Storage 9985 System
Sun Storage 9990 System
IBM AIX on POWER Systems (64-bit)

Symptoms

On AIX, when a dlmvaryonvg or varyonvg is attempted to a volume group built on devices presented by hdlm, the command fails with the following error message:

0516-013 varyonvg: The volume group cannot be varied on because there are no good copies of the descriptor area.

Cause

When volume groups built on hdlm devices are varied on, if reservation level is set to 2 (default), the underlying hdisks are reserved using scsi3 persistent group reservations. The reservations should be removed on varyoffvg but may not have been removed due to a system problem.

Solution

Here is an example using dlmvg1 which fails to varyon, showing the recovery steps.

# dlmvaryonvg dlmvg1
0516-013 varyonvg: The volume group cannot be varied on because there are no good copies of the descriptor area.

determine what devices make up dlmvg1:

# lspv | grep dlmvg1
dlmfdrv1        0004014f5aff21af                    dlmvg1

The line above shows dlmvg1 is made up of the single device dlmfdrv1.

To determine what hdisks make up dlmfdrv1:

# dlnkmgr view -drv | grep dlmfdrv1
000000 dlmfdrv1 hdisk3 9970/9980.30221.0102
000001 dlmfdrv1 hdisk5 9970/9980.30221.0102

We see in the line above dlmfdrv1 is made up of two paths, one through hdisk3 the other hdisk5.

To determine if either has a reservation on:

# dlmpr -k
self Reservation Key : [0x0000000004014f4c]
hdisk0     Reservation Key : [0x????????????????]
hdisk1     Reservation Key : [0x????????????????]
hdisk2     Reservation Key : [0x????????????????]
hdisk3     Reservation Key : [0x0000000004014f4c]
Regist Key : [0x0000000004014f4c] , Key Count : 2
hdisk4     Reservation Key : [0x????????????????]
hdisk5     Reservation Key : [0x0000000004014f4c]
Regist Key : [0x0000000004014f4c] , Key Count : 2

From the output above we see reservations on hdisk3 and hdisk5. This is why we can't vary this vg online. Note the self Reservation key may be different from the Reservation Key if a reboot has taken place.

To clear the reservations we use dlmpr -c hdiskN.

dlmpr -c hdisk3
dlmpr -c hdisk5

This should clear the reservations allowing the volume group to be varied online.

Additional Information

This applies to a single host environment. If another host has access to this volume group, it may have the volume group varied on line and the devices reserved. That would be a purely administrative issue.

Applies to HDLM 5.1 and later.

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