Mtree creation in Data Domain fails with error MTree "/data/col1/<mtree name>" already exists
Summary:
This KB article describes how to create an mtree in Data Domain if it is throwing the error "MTree "/data/col1/" already exists
This article applies to
This article does not apply to
This article is not tied to any specific product.
Not all product versions are identified in this article.
Instructions
User is unable to create an MTree in Data Domain and getting the error such as "MTree "/data/col1/<mytest_mtree>" already exists, for example:
sysadmin@dd# mtree create /data/col1/mytest_mtree **** MTree "/data/col1/mytest_mtree" already exists.
Of course, if the MTree with the given name exists, the error is expected, however, there are times when the MTree with the same name has existed in the past, but has since been deleted, and still the "mtree create" command will fail in the same way.
Additional Information
The cause for this alert is that somebody had already created and (recently) deleted the MTree named mytest_mtree, however DD clean has not run yet since. Until the cleaning is started, the MTree is in "Deleted" state, but still exists in the FS. Verification can be made using below command , a "D" besides the MTree name indicating it has been deleted by DD clean has not been run yet.
For the MTree to be created again, you just need to start the file system cleaning. After less than one minute all the "D" MTrees will have been removed, and hence you will be able to create the MTree again. There is no need to wait for the DD clean to complete, and therefore if not the best time for you to have clean running, you may stop it:
At this time if you create the MTree again, the command will be successful:
sysadmin@dd3300-brentford# mtree list Name Pre-Comp (GiB) Status ----------------------- -------------- ------ /data/col1/backup 0.0 RW /data/col1/mytest_mtree 0.0 D
For the MTree to be created again, you just need to start the file system cleaning. After less than one minute all the "D" MTrees will have been removed, and hence you will be able to create the MTree again. There is no need to wait for the DD clean to complete, and therefore if not the best time for you to have clean running, you may stop it:
sysadmin@dd# filesys clean start [ Wait for one minute] sysadmin@dd# filesys clean stop
At this time if you create the MTree again, the command will be successful:
sysadmin@dd# mtree create /data/col1/mytest_mtree MTree "/data/col1/mytest_mtree" created successfully.
Affected Products
Data DomainProducts
Data DomainArticle Properties
Article Number: 000019794
Article Type: How To
Last Modified: 18 Sept 2025
Version: 3
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.