Data Domain: Local storage size exceeds the maximum required metadata capacity for this configuration

When storing data in the cloud (either as Long-Term Retention, LTR, in addition to Active tier storage, or in the case such as yours with ATOS, for Active tier sitting in cloud) there is the need to have "local" metadata coupled to the real backup data being stored remotely (in the cloud). For LTR, DDs have to be added to some pre-defined amount of local hardware storage as cloud metadata.

For DDVE ATOS, local-metadata storage has to be provided as well, only in this case disks are provisioned from the hypervisor, and while not necessary "local" (or "hardware"), they are still accessed through (paravirtual) SCSI protocol and at least some guarantees for disk IO and bandwidth exist. These cannot be guaranteed for object storage though. For regular operations and for DD, clean as well it is necessary to have a certain degree of performance guaranteed, and also to run some operations "locally" (in local, metadata storage) rather than going back and forth on the net to the cloud provider, which may also incur additional costs.


The design for both LTR and ATOS is for datasets which would achieve approximately x10 times data reduction ratios, and hence, to produce a given amount of metadata (approximately 10% of metadata space needed for the LTR or ATOS post-comp capacity licensed).

When the amount of disk space allocated for local-metadata has reached the expected maximum in DDVE ATOS, when trying to add further storage from the CLI, the warning is presented:

SE@dd.example.com## storage add tier active dev14 Checking storage requirements... ** Local storage size exceeds the maximum required metadata capacity for this configuration. Do you want to continue? (yes|no) [no]:

 

 

By design it is expected local-metadata will only be needed as much as 10% licensed post-comp, in the case for the example:

Active tier maximum capacity: 96.0 TiB Estimated local-metadata capacity needed: 10%*96 TiB = 9.6 TiB

Attempts to add more disk storage beyond that results in a warning for DDVE ATOS, when trying from the CLI. This is only an informative warning though, and the command question may be answered "yes" and the command proceeds. If doing the same from the UI, there is no warning presented, and the operation proceeds without asking for confirmation.

There is nothing a customer needs to do other than being aware the amount of disk space being added to local-metadata in DDVE ATOS is already beyond the estimated maximum needed for the licensed capacity and the DDVE capacity. This is not an error, but an informative warning. Customers may continue using the DDVE normally and adding more local metadata capacity as needed.

For more information about DDVE local metadata capacity and why it may be filled up when already sized as per the documentation, please read the linked DD KB article below:

Data Domain: Data Domain Virtual Edition(DDVE) which are Cloud deployed (ATOS), may run out of Local-Metadata Storage