As previously announced, the Nagios plugin check_equallogic now catches etherrors. After some user feedback Martin Conzelmann and I decided to add warning and critical thresholds in case ethernet packet errors were detected and when the counter doesn't increase. So if your Equallogic shows etherrors but they don't increase, you might use the thresholds to be notified when the packet errors increase.
Another important update is a bugfix of the volumes check, where the subtraction of the zero-sized volumes was missing a variable (thanks to Martin once more). Some Equallogic models have several zero-sized volumes, some do only have one. Depeding on which EQL model you use, the volumes check might have worked fine before. In any case, with this version the check should work on all models.
New version number of the plugin is 20110404. Enjoy and as always, thanks for your feedback.