all my tapes has been marked as full in one night, however this only happened to one pool.
the media belonging to different pools are all fine.
I searched the support forum and found what could be the cause for this.
This occured due to dirty tape drives, we have run out of cleaning media and the library has been sending alerts that drives need cleaning.
What I want to know is how do I get the data back that was on these tapes as they display 0KB and Full.
I changed the mode of a few tapes to appendable hoping that it will display the true percantage of data on the tape.
It still says 0KB and appendable.
Is there perhaps a command I can run to get the data back onto the tapes ?
Are you sure that on tapes marked as full and 0KB written any data was written?
If you believe that there should be data on it you can try to use scanner command. First run it with -n option (and as I remember -i) to check this tape without index and media database changes.
I believe what happened here is you had a problem with your tape drives one night and it marked a load of tapes as full even though no data was written to them. You then set the tapes to appendable after resolving the drives issues and you are unsure as to whether or not you have lost data as the tapes show up as 0KB. There are two possibilities here, firstly that no data was written to the tapes in the first place so there is nothing to worry about, the second is that the tapes had data on and rather than setting them to appendable you relabelled them which is not a good thing as you would lose your backups. Judging by your second comment it sounds like the first scenario is what applies here and you have had no data loss.