Need info on option "Maximum I/O streams per volume"

Disk storage units allow you to limit the number of concurrent write jobs that use the storage unit, however there are no limits on the number of read jobs (restores and duplications) that may be accessing the same disk pool at the same time and it is also possible to configure multiple storage units to access the same disk pool simultaneously. This can give rise to unexpected I/O contention on the disk pool. By setting the Maximum I/O streams per volume option on the Disk Pool, you can limit the total number of jobs that access the disk pool concurrently, regardless of the job type. While the disk pool is maxed out with backup jobs that are writing images to the device, no duplication jobs are allowed to start reading from the device. (The one exception to this rule is that restore jobs are allowed to read from the Disk Pool even if the maximum configured number of input and output streams is already being utilized.)

When you enable the Maximum I/O streams per volume option on the Disk Pool the default number of streams is 2. Although the optimal number of streams per volume will vary depending on the disk type, a general guide line to minimize contention would be to divide the maximum concurrent jobs count for all the storage units using the disk pool by the number of volumes in the disk pool.