Unknown Dg appears in Disk Groups with some or all disks

Question

Hello,
Since support from Symantec is slow (not every case, but this time), I am asking this on forum.
I am doing a new installation and suddenly I have this new DG called "Unknown Dg". There are disks with status foreign and type Dynamic. I cannot do anything with these disk (oh powerfull SFW). Usually I can destroy DG or remove disk from DG etc, but not in this case.
Reason for having this situation:
- I made two cluster Disk Groups with same name on different servers with different disks and suddenly disks from this Disk groups are in disk group Unknown Dg
- I reinstalled SFW and suddenly all disks from all dynamic Disk groups are in Unknown Dg

I searched documentation and found this:
If the cluster software attempts to fail over a disk group to another node that has a disk group with the same name or if you move a disk group to another node that has a disk group with the same name, unpredictable results can occur. (well now we know the result).

I searched internet and found this: http://seer.entsupport.symantec.com/docs/287444.htm (there is part telling you to reinstall SFW - but this makes it even worse)

I found also this:
vxtool is used to clear the SFW&nbsp;Private Region from a disk and would be used in instances when you were attempting to destroy a Disk Group or remove a problem Disk that has a corrupted private region on it. The resetmbr clears the private region and writes a new signature to the disk.

Do you think that vxtool can help me with this ?

my config: w2k3 r2 sp2, VSFW 5.1 sp1, fiber HBA qlogic QLE2460, and IBM DS8300 array

hraju · Accepted Answer

So I worked on this with Symantec support. We tried vxtool but with no avail, because we got mesages saying that disc is not usable !

but after I managed to have all disks back. What I did is:

- installed all recommended Windows fixes (2 recommendation from qlogic - HBA manufacturer, 2 recommendation from IBM manufacturer of SDD DSM)
- updated driver of HBA - STOR Miniport (to recommended level)
- updated firmware, bios, fcode and EFI of Qlogic HBA (everything is in one download package - I did it via Sansurfer FC HBA GUI Manager)
- installed Subsystem Device Driver DSM Version 2.4.2.1-2 from IBM
- configured all two HBAs from Sansurfer FC HBA GUI Manager

this helped me to get back all disks, but one - quorum disk was still missing in VEA

so removed both cluster nodes from cluster with command "cluster node /forcecleanup"

and than when I did a rescan, I was able to import Disc group with no missing discs. Then I destroyed all disc groups (except BasicDG with boot disc). And I am going to configure this cluster again.
So I think, that problem was because the servers were part of MSCS cluster.

But first I will create a quorum disc group and then create MSCS cluster. I hope it will work out this way.

I will let you know about the outcome.

wally_heim · Answer

Hi hraju,

UnknownDG is created when SFW detects a problem with the private region that it can not handle.&nbsp; This can be from many different reasions included corrupt private region or in your case it is a duplicate diskgroup name with a different DGGUID.&nbsp;

If you know which disks you put in which disk group you can simply offline (windows 2008) or disable the disks from one disk group.&nbsp; Then a rescan should allow the other disk group as OK.&nbsp; Change the name of the disk group when importing via VEA (adjust any cluster resources to match.)&nbsp; Now you should be able to online/enable the disks that you disabled before and the disk group on those disks will be available with the original name.

Thanks,
Wally

FYI - if you are truely in a down situation as you mentioned with no access to your data/disk groups, open the case as a Servirty 1 case and ask to be live transferred to the next available TSE.&nbsp; This will get you placed at the top of the&nbsp;support queue.&nbsp; We have a 30 minute SLA for Sev1 live transfer cases.

hraju · Answer

I was able to "recover" one of those disks, but the secondone is still at Unknown Dg. And this is the only one in this group.

I have a different setup (different servers) where all disks are in Unknown Dg (this is after I reinstalled SFW) . And each time I do rescan, the displayed status of disks change randomly, i.e.:
This is from the same VEA before and after rescan:

Here is the list of disk inside Unknown Dg: (disk with OS is only usable disk in this case):

hraju · Answer

This is new installation, so it is not that critical. I was thinking about clearing private region of disks, since there are no data yet.

wally_heim · Answer

Hi hraju,

The changing of the way the disks are displayed are due to the "unpredictable results can occur" comment that you mentioned before.&nbsp; When a rescan is issues the Object Bus is cleared out and recreated based on what SFW finds when it scans the disks on the server.&nbsp; Depending on the order that the scan is done and how fast each device responds the results can be different when there is conflicting information as in your case.

The vxtool utility can be used the wipe the private region from the disks that you are having problems with.&nbsp; The issue is that vxtool is a tool that is intended for Symantec's use only.&nbsp; Because of the power of this tool we recommend that customers only use it when directed by Symantec Support.

Thanks,
Wally

hraju · Answer

I see. I found this tool on symantec web, but it is password protected (so I figured out that only symantec employees can use it). All I can do is to wait for symantec support, now. Thank you for help anyway.

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Unknown Dg appears in Disk Groups with some or all disks

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