After upgrading to 8.2.1 the memory consumption on the appliance seems to be higher than before the upgrade.
The mechanism for managing processes taking up high amounts of memory may have incorrectly managed those processes.
Upgrade to Security Analytics 8.2.1-2 (8.2.1 NSR2) or 8.2.2.
8.2.1-2 is available here: https://license.soleranetworks.com/upgrades/NSR821-2