On 10/28/2016 02:37 PM, Chris Hoogendyk wrote: > It also knows what a particular DLE can be compressed to based > on the history. If the tape drive is doing the compression, then it is a > black box. Amanda doesn't know what the DLE got compressed to, and it > doesn't know how that relates to the capacity of the tape. That makes > planning more difficult.
This might be a good place to plug an idea I floated back in January: http://marc.info/?l=amanda-hackers&m=145312885902912&w=2 ... it turns out in the SCSI standard for tape drive commands, there are ways to ask the drive, after writing each fileset, "hey drive! what did that last set compress to?" I haven't had time to pursue it ... I think the part I could probably do without help is teaching the tape driver to ask the drive for the statistics. It might take a more seasoned Amanda hacker to work out how to get those numbers stored in the history, similarly to what happens with software compression, so they can be used by the planner later. It still does strike me as worth exploring.... Chapman Flack
