Grant Fritchey (7/23/2013)
You can do a COPY_ONLY backup on the secondaries. But, you cannot use a COPY_ONLY backup as part of a point in time recovery. The entire concept behind the COPY_ONLY backup is to avoid dealing with the transaction log and differentials.
That's news to me. You can definitely do a restore of a COPY_ONLY backup with NORECOVERY and restore subsequent log backups...
Differential restores are obviously not possible. The resetting of the differential base is the entire concept of COPY_ONLY backups, it doesn't change any behaviour relating to transaction logs.