Dell Unity: How to calculate Subscription Space

What is Subscription in a Thin Pool?
For thin provisioning, the total storage space subscribed to the pool. All pools support both standard and thin provisioned storage resources. For standard storage resources, the entire requested size is allocated from the pool when the resource is created, for thin provisioned storage resources only incremental portions of the size are allocated based on usage. Because thin provisioned storage resources can subscribe to more storage than is allocated to them, pools can be over provisioned to support more storage capacity than they possess.

Unisphere automatically generates notification messages when total pool usage reaches 85% of the pool's physical capacity. (You can customize this threshold).

How to calculate Subscription in a Thin Pool?
Theoretically the subscription space is the total allocated space of all storage resources under the pool (ex: LUNS, FileSystems, Snaps ....)

To Check the subscription percentage from the user interface:

Click Pools under Storage, then double-click the Pool you want to check, after that choose Usage Tab you find the Below view:



In order to see the breakdown of this percentage in details Run the following commands:

- Open SSH connection to the Unity, then use svc_arrayconfig H which creates the telemetry html file. 

08:50:16 service@(none) spb:~> svc_arrayconfig -H
/EMC/backend/service/configuration_history/20161122_085022_ARRAYSERIALNUMBER_EMC-UEM-Telemetry.html
08:50:51 service@(none) spb:~>

Using WinScp to copy the file to the desktop open it and you can view in details everything regarding the pool.

Open the Telemetry file select Storage - Pool then check the details of the following:

- metadataSizeSubscribed
- sizeSubscribed
- snapSizeSubscribed

The following uemcli commands can also be used to check the following details:

uemcli /stor/prov/luns/lun show -detail   >>> Views all  LUNs 
uemcli /stor/prov/fs show -detail              >>> Views all File systems 
uemcli /prot/snap show  detail                >>> Views all Snapshots.


Additional knowledge base articles referencing over subscribed Pools:

Dell EMC Unity : Pool size is showing over subscription (Customer Correctable)
Dell EMC Unity: Block/File storage resources invalidation behavior for over subscribed pools