Data Domain Mtree cannot be deleted

Sometimes Data Domain Mtree cannot be deleted i.e. due to lack of proper license,

This can be caused if you replicate VTL Mtree to Data Domain without VTL license and you can get error as below:

mtree delete /data/col1/VTL_mtree
**** MTree "/data/col1/VTL_mtree" contains a VTL Pool, cannot be deleted.

There is workaround to to resolve the issue:
1. Create empty mtree.
2. Run fastcopy to overwrite the VTL mtree with an empty mtree.
3. Restart file system.
4. Delete the VLT mtree and the empty mtree.


Example command list:

mtree create /data/col1/empty_mtree
mtree list
filesys fastcopy source /data/col1/empty_mtree destination /data/col1/VTL_mtree
mtree list
filesys restart
mtree delete /data/col1/empty_mtree
mtree delete /data/col1/VTL_mtree


Example output:

sysadmin@dd-01# mtree create /data/col1/empty_mtree
MTree "/data/col1/empty_mtree" created successfully.
Quota soft limit: none, hard limit: none(*)
 (*) Quota is disabled. Quota limits not enforced.


sysadmin@dd-01# mtree list
Name                                 Pre-Comp (GiB)   Status
----------------------------        --------------         ------
/data/col1/VTL_mtree              5860.0             RW
/data/col1/backup                           0.0             RW
/data/col1/empty_mtree                  0.0             RW
----------------------------         --------------        ------
 D    : Deleted
 Q    : Quota Defined
 RO   : Read Only
 RW   : Read Write
 RD   : Replication Destination
 RLGE : Retention-Lock Governance Enabled
 RLGD : Retention-Lock Governance Disabled
 RLCE : Retention-Lock Compliance Enabled


sysadmin@dd-01# filesys fastcopy source /data/col1/empty_mtree destination /data/col1/VTL_mtree

Destination "/data/col1/VTL_mtree" already exists.
Proceeding will overwrite its content with "/data/col1/empty_mtree".
        Are you sure? (yes|no|?) [no]: yes

ok, proceeding.

Creating snapshot "FASTCOPY-2019-03-13-04-28-17" with one-hour retention period...done
Use this snapshot to recover in case of a mistake.

(00:00) Waiting for fastcopy to complete...
Fastcopy status: fastcopy /data/col1/empty_mtree to /data/col1/VTL_mtree: deleted 1046 files, 1 directory in 1.05 seconds

sysadmin@dd-01# mtree list
Name                              Pre-Comp (GiB)   Status
----------------------------   --------------           ------
/data/col1/VTL_mtree                      0.0        RW
/data/col1/backup                              0.0       RW
/data/col1/empty_mtree                    0.0        RW
----------------------------   --------------           ------
 D    : Deleted
 Q    : Quota Defined
 RO   : Read Only
 RW   : Read Write
 RD   : Replication Destination
 RLGE : Retention-Lock Governance Enabled
 RLGD : Retention-Lock Governance Disabled
 RLCE : Retention-Lock Compliance Enabled

sysadmin@dd-01# filesys restart

This action will restart the file system.
Applications may experience interruptions
while the file system is restarted.
        Are you sure? (yes|no) [no]: yes

ok, proceeding.

Disabling filesystem:
Please wait..............
The filesystem is now disabled.
Enabling filesystem:
Please wait...............

The filesystem is now enabled.

sysadmin@dd-01# mtree delete /data/col1/empty_mtree

Deleting an MTree will destroy all data in the MTree.

If there are any NFS exports, CIFS shares, VTL tapes, DDBOOST storage-units, Replication Contexts or Physical Capacity Measurements configured for this MTree, they need to be manually removed/edited. Do you wish to continue?

        Are you sure? (yes|no) [no]: yes

ok, proceeding.

MTree "/data/col1/empty_mtree" deleted successfully.

sysadmin@dd-01# mtree delete /data/col1/VTL_mtree

Deleting an MTree will destroy all data in the MTree.

If there are any NFS exports, CIFS shares, VTL tapes, DDBOOST storage-units, Replication Contexts or Physical Capacity Measurements configured for this MTree, they need to be manually removed/edited. Do you wish to continue?

        Are you sure? (yes|no) [no]: yes

ok, proceeding.

MTree "/data/col1/VTL_mtree" deleted successfully.

sysadmin@dd-01# mtree list
Name                           Pre-Comp (GiB)   Status
----------------------------   --------------        ------
/data/col1/VTL_mtree                      0.0      D
/data/col1/backup                              0.0     RW
/data/col1/empty_mtree                    0.0     D
----------------------------   --------------        ------
 D    : Deleted
 Q    : Quota Defined
 RO   : Read Only
 RW   : Read Write
 RD   : Replication Destination
 RLGE : Retention-Lock Governance Enabled
 RLGD : Retention-Lock Governance Disabled
 RLCE : Retention-Lock Compliance Enabled

Data Domain - suddenly monitoring shows disk unknown

Sometimes when you monitor data domain your monitoring software can suddenly report disk as "UNKNOWN" however data domain works as normal.
This is caused by data domain management services misbehavior.
To resolve it you should run below commands:

1. SSH to your data domain

2. Enter SE mode:

system show serialno
(make note of the serial number)
priv set se
(use the serial number as the password)

3. Run the following:

reg set config.crontab.diskinfo_reset = "*/5 * * * * root /bin/killall -9 ssm"

4. Wait for at least 10 minutes and after that time run this:

reg removekey config.crontab.diskinfo_reset