what is 'Maximum concurrent write drives' and 'Maximum streams per drive' in STUs
Maximum concurrent write drives
The Maximum concurrent write drives setting specifies the number of tape drives that NetBackup can use at one time for jobs to this storage unit. The number of tape drives available is limited to the maximum number of tape drives in the storage device. If a job contains multiple copies, each copy applies toward the Maximum concurrent write drives count.
You may want to limit a storage unit that has 5 drives to only use 4 for backups, so you have 1 available for restores (for example)
http://www.symantec.com/business/support/index?page=content&id=HOWTO33367
Maximum streams per drive storage unit setting
The Maximum streams per drive storage unit setting determines the maximum number of concurrent, multiple client backups that NetBackup can multiplex onto a single drive. The range is from 2 to 32.
