Here’s the description of this issue from EMC:
EMC has become aware of a compatibility issue with the new version of MacOS 10.7 (Lion). If you install this new MacOS 10.7 (Lion) release, it will cause the data movers in your Celerra to reboot which may result in data unavailability. Please note that your Celerra may encounter this issue when internal or external users operating the MacOS 10.7 (Lion) release access your Celerra system. In order to protect against this occurrence, EMC has issued the earlier ETAs and we are proactively upgrading the NAS code operating on your affected Celerra system. EMC strongly recommends that you allow for this important upgrade as soon as possible.
Wow. A single Mac user running 10.7 can cause a kernel panic and a reboot of your data mover. According to our rep, Apple changed the implementation of SMB in 10.7 and added a few commands that the Celerra doesn’t recognize. This is a big deal folks, call your Account rep for a DART upgrade if you haven’t already.