The DIAG_MAIN node will go into error a little less than once a day, and report:

File "/ligo/apps/linux-x86_64/cdsutils-497/lib/python2.7/site-packages/cdsutils/avg.py", line 67, in avg
2015-09-21T01:10:35.46180     for buf in conn.iterate(*args):

RuntimeError: Requested data were not found

(screenshot attached)

While this only requires the operator to reload the node, the cdsutils avg package is used in other nodes such as ISC_LOCK and OMC_LOCK (and others that I can't think of off the top of my head). This inconsistancy also omits its use in the DIAG_CRIT node, for fear that it will not be able to find the data, bring the node into error, and then out of Observation.

Operators: Please log and screenshot the Guardian log any time that a Guardian node goes into error. This will help us diagnose the problem, or others, faster.