Heavy disk usage on Media server when idle

Hi all,

Our NBU 7.6.3 deployment is still in pre-production and yesterday, for the first time we ran a couple of test VM backups.  The backup completed successfully however almost immediately after the backup completed, and still 24 hours later, I see heavy disk reads on the LUN that hosts the Dedupe store.  If I look at the Disk tab within Windows Resource Monitor I see the following (see attachement).

This storage is connected via iSCSI if that makes a difference...

Is this expected?

Thanks in advance,

Graham