Troubleshooting mount drive problems

[Natalie]

HI All,

Current I have VCS installed on 2 computers using a SAN for datastorage. If one machine fails what SHOULD happen on the functioning machine is the D drive (points to the SAN) should be imported on the machine taking over.

While testing the failover the Mount_v resources turned with a question mark in the VCS console manger. On one server had the disk imported (its part of a dynamic group) but the dynamic group has disappeared on the second server. Attempts to re-create the dynamic disk on the second machine fail with "v-39-58645-227 Partition was not found on the disk"

This is something that was working without a problem for a while. All that I have changed is volume name of the mount V resource in an attempt to figure out why the failover wasn't happen automatically.So far I haven't found anything help on symantec support site.

Can anyone help me with tools or information on how I can troubleshoot this problem ?

[Gene_Henriksen]

First, let me say D is not a good letter for failover drives. If anyone plugs in a USB drive, adds a DVD/CD or whatever, D could be occupiend and prevent failover or even cause a concurrency viloation.

Second, when a dynamic disk group is imported on one server, it is pretty much invisible to the other because of disk reservations. If you had 2 servers S1 and S2, and decided to add volume V1 on S1, S2 couldn't see it and would therefore show the red question mark.

When configuring cluster resources, it is best to test them on both systems before putting them under cluster control for this reason.

It is good that the attempt to re-create the DG failed, otherwise you could have overwritten the original one. This is the reason we protect DGs that are imported.

IF you can afford some down time, save the configuration (haconf -dump -makero), stop VCS (hastop -all) then import the DG on the other server to be sure both systems have seen the DG.

How did you change the name of the MountV resource? Cut and paste is one way, offline change to main.cf is the other. Either way, both systems now see an new resource and need to verify the status.

[Natalie]

Thanks for your response Gene.

Both computers were seeing the SAN drive before the clustering. Actually computerA was turned off and ComputerB still couldn't see the dynamic disk group. Actually to be more precise, compB can see the volume, but the Dynamic disk group has disappeared. When I powered on compA, the Dynamic disk group and volume came up with no problem. So I do think I will need to figure out what went wrong on CompB

To change the volume name (previously nothing was there), I simply typed the name in the Volume name attribute of the mountV resource properties.

My link to the site with the VCS is down but as soon as it is back up I'll try you suggestions and let you know the outcome.

[Gene_Henriksen]

You had said you type the MountV resource name and I wasn't sure if it was the attribute of the resource (the name of the actual volume) or the resource itself.

It is hardto understand how it could see the volume and not the Disk Group. The device to see the Volume is only created on import of the Disk Group.

[Natalie]

Its the resource attribute that had no name, I changed it to the name of the volume.

Yes it is strange that the VOLUME is present and the dynamic disk group disappeared. But so there is no confusion. If you look in "my computer" the drive\volume is not present. When you look in volumes in the Veritas Enterprise Admin the volume is present. But under Disk Groups you only see the basic disk group. Not the dynamic disk group I created.

Usually you can see the group, and volume with the blue import volume icon and if you choose to import disk, they are imported without a problem.

No site connection yet but can you suggest any tool that can help me troubleshoot the problem ?

[Gene_Henriksen]

Rescan both systems. Make sure ou can see the disk groups.

Make sure the disk group is cluster dynamic:
vxdg list
name:                  MyDG
Disk group type:  Dynamic (cluster)


Also in vxdg list you can comapre the DiskGroup IDs (make sure they are seeing the same DG) and the status.

[Natalie]

many sick days and days with no internet connectivity later...... back to the thread. The problem has been solved and hopefully other and learn from my bad experience. I've been as detailed as I can.

1.  The reason the second server could not see the drive on the SAN was by design. It was in use by the cluster and therefore couldn't be used anywhere else.

2. The reason(s) I had the issue with the mount_V resource were

 (a) the dynamic group on compB was NOT setup as a CLUSTERED dynamic group.

 (b) Mount_V had an incorrect volume name. I used the name found in the my computer listing. I should have used a tool the name of will find and post later.

(c) The drive letter in the mountV resource list should have been "D:" not "D"

(d) The Veritas cluster service helper on both computers were not started because of the password of the user was changed.

Gene you were correct in your suggestions. But I needed symantec support to help me with the other issues that primaryily stemmed from my inexperience.