Message: app.log.alert: <redacted_hostname>: snapdrive 5.2.2D4 for UNIX: (4) snap delete
failed: host_name=<redacted_hostname>, host_os=SunOS, host_os_release=5.10, host_os_version=Generic_Virtual, No of controller=4, PM/RBAC=native, Host Virtualization=No, Multipath-type=none, Protection Enabled=No,
Protocol=fcp,9046: Failed to remove snapshot smo_<db>_f_h_2_2c9790874ee1480b014ee14814e80001_0_daily on storage system <redacted_lif_name> : This Snapshot copy is currently used as a reference Snapshot copy by one or more SnapMirror relationships. Deleting the Snapshot copy can cause future SnapMirror operations to fail.
Description: This event is issued when an application is in a condition that should be corrected immediately.
Starting to see these messages with more requency, just wanted to make sure they're not something to be concerned about... but given that SnapDrive is preventing the deletion to ensure the SM relationship is preserved strikes me as a GOOD thing.
It looks like the SMO created snapshot that's trying to be deleted is newer than the snapmirror snapshot which is needed by snapmirror. Check your snapmirror scheduled time and the snapshot retention in SMO.