Copy only backups

Copy Only Backups - explanation and when to use

Copy only backups are best used to make an adhoc full backup where you do not want to interfere with the database backup schedule and want this backup to remain independent.
Copy only backups are the same as full backups in that they do not effect the log chain, however if a differential backup is part of the strategy then creating an adhoc copy only backup will mean if the next backup in the schedule is a differential backup it will not use the copy only backup as the differential backups base, but use the previous (non copy-only) full backup instead.
We might want to use this method of backup for our weekly backup (our retention period may be smaller than the full weekly backup or we may simply want to have independent control of these backups without worrying about the effects of subsequent differentials).  For example after this area has been archived by acronis we may wish to manually clear it down (again depending on backup policy).
We may also want to use this method to backup a database to a differrent location just prior to a change, again not wanting subsequent differentials to become dependent on this.
If we have a backup plan without differentials then there is no useful need to use a copy only backup.
Note that transaction log backups taken after a copy only backup can still be restored providing there are no breaks in the chain as per a normal full backup.