SAN might go offline because a second might be added to the clock
Excerpt: ETA 201584: Avamar Data Store, Avamar Server: Avamar Gen4 and Gen4S nodes may experience performance issues or go offline related to a Leap Second UTC addition.
I had some Debian boxes fall over during the 2012 leap second adjustment. It was a kernel bug, since fixed.
There's another leap second scheduled for the end of June this year. Probably a good idea to upgrade to a kernel newer than 2.6.32 before then.