my filer is [NetApp Release 8.2.5 7-Mode], i am using it as backup, i have created volumes and used it as snapmirror targets but the problem is aggregate is almost full and i need to delete some snapshots from the target volumes, when i tried i recieved the error: Snapshot operation not allowed on a read-only volume, is there a way i can forcibly delete these snapshots without touching the source filer or breaking the snapmirror ?
One thing that can make a difference too is the snapshot size. If you have a high change rate, then consider identifying why there is a high change rate. Do you have swap/tempdb files in the same volume as the rest of the data? Do you lump your data together into a singular bucket? Having smaller buckets can help, and reduce overall snapshot size.
You'll probably need to delete space on the source to free up space on the destination unfortunately. SnapMirror locks the volume down so it can't be used until it is released.