I believe that "Simultaneous write operations/Concurrent Write Sessions" is just a limit of how many write operations (i.e. backup jobs) that Backup Exec will allow to run at once. Basically similar to the limit of how many tape drives you have in your tape library limits the number of jobs that can run at once.
If you are only running a single backup job, then the setting has no performance impact. If you want to run multiple jobs simultaneously, then you will need to test on your particular environment to find the sweet spot for total optimum performance.
thx for your awnsers.
Direct after backup2disk theres a clone job to tape, so the raid is just a temporary solution and for that should be as fast as possible.
assumed something like this allready but wasnt sure.
Last night the disk job ran with avarage 5,5GB/min with setting to 2.
Will change it to 1 just for testing purpose and reply the result.
changed it to 1: no siginificant changes (sometimes a little bit faster/slower) so it seems, this option is really only to specify how many jobs can simultaneously write to this disk an not how many write streams are established.
You can configure how many jobs can write simultaneously to your B2D storage. You might think that this also puts a hard limit on the number of jobs that run simultaneously. As it appears this is not the case.
Since BEX writes B2D data in .BKF files, there will be small time gaps between finshing one .BKF file and starting the next one in a job. Occasionally BEX manages to start another job in that gap. Exact circumstances unknown.