If you are checking your filer with the Snapshots plugin, you may get an error like:
Can't call method "attr" on an undefined value at /opt/.../lib/nagios/plugins/check_netapp_pro/checks/Snapshots.pm line 289.
The reason for this is, that the SnapDrive application creates flexclones, which are created, mounted on a backup server, backed up and then deleted.
With the present versions of the Snapshots plugin you can exclude these volumes with
-X ^sdw_cl_ (SnapDrive for Windows) or
-X ^sdu_cl_ (SnapDrive for Unix).
In the next version of Snapshots the handling of missing (disappeared) volumes will be already improved, so that if these temporary volumes were not explicitly excluded they are just skipped and a hint will be printed to stdout showing how many volumes were ignored by the check.
$ check_netapp_pro.pl Snapshots -H filer
NETAPP_PRO SNAPSHOTS OK - 151 snapshots on 52 volumes checked. 6 volumes not found in store and ignored.
$ check_netapp_pro.pl Snapshots -H filer -X ^sdw_cl_
NETAPP_PRO SNAPSHOTS OK - 126 snapshots on 27 volumes checked.
31 snapshots skipped because of --include/--exclude settings.
The second example is a bit more precise in my opinion, as it explicitly skips only clones created by the SnapDrive application (as long as everybody sticks to that naming-convention).