SnapMirror TDP 7mode to Cmode LUNS - why are volumes hidden?

atwilson — Wed, 04 Jun 2025 15:21:31 GMT

been puzzling over a problem while testing our 7mode to Cmode transition scripts for Exchange 2010 LUNs that are connected to Win2008R2EE hosts.

We are using the SnapMirror TDP method. source is 7mode 8.1.4p9D18, destination is Cmode 8.3.2P2

I setup a couple of extra SnapMirrors to test the cutover procedure and to confirm the vols are mountable after cutover using SnapDrive (7.1.3P3)

We encountered trouble mounting the vols with SnapDrive, which would timeout after 120seconds (spent many hours with NetApp support troubleshooting)

Interestingly, SnapDrive waits for the arrival of the disk which is successful, we can see the disk arrive in DiskMgmt.msc, filesystem is recognized as NTFS, healthy.

SnapDrive then waits for the volume to arrive, which never happens, and SnapDrive times out.

We can manually assign a drive letter and access the contents of the disk, everything looks intact.

Eventually we discovered using DiskPart that the transitioned luns are "hidden" so SnapDrive cannot see the volume arrive.

i.e. vol 5 below

DISKPART> list vol

Volume ### Ltr Label        Fs     Type        Size     Status     Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0     R                       DVD-ROM         0 B No Media
Volume 1         System Rese NTFS   Partition    100 MB Healthy    System
Volume 2     C                NTFS   Partition     39 GB Healthy    Boot
Volume 3     S   Swap         NTFS   Partition     11 GB Healthy    Pagefile
Volume 4     D   Data         NTFS   Partition     39 GB Healthy
Volume 5         M:\DB03\     NTFS   Partition   1434 GB Healthy    Hidden

We can clear the hidden attribute and then SnapDrive can mount and unmount the disk no problem. The setting sticks with the lun.

Question is - why are these transitioned luns set to hidden?

The source luns are not hidden.

I cannot find any documentation about this.

NetApp support seems to be just as perplexed so far as we are.

Thanks

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SnapMirror TDP 7mode to Cmode LUNS - why are volumes hidden?