update :
When i use on my dir/storage, Maximum Concurrent Jobs = 4, bareos launch 4 job at the time on 2 drive.
But device (tapedrive1 and tapedrive2) was set at : Maximum Concurrent Jobs = 2.
For my VIrtualMachine-Full-Pool, i got 2 dedicated LTO-8 tape (2*12TB) with Maximum Volumes = 2 .
The idee behind is force bareos to use only one tape and when tis tape was full, switch to the second.
I have found a trick : label the second as Used... But for 2 1st batch of jobs, bareos load the tape A00001L8 on the
tapedrive1, and to the 2 2nd batch of jobs, bareos want use the 2nd drive (tapedrive2). The resulat was when 1st bastch was enend, he unmount the tape
A00001L8 in
tapedrive1and mount on
tapedrive2... and block other job from other pool...