Netbackup Stream Counts on Disk Target Reads
Is there any Tuning Tricks or Parameters that can be optimized to Increase the effective number of streams for Reading Restores from Disk Based Storage Units?
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See also 'Disk Thrash'
NBU uses a scheme called 'multiplexing' to write to tape. Data is read from disk and written to shared memory. The shared memory segment is written to tape. Each segment of a backup image are intervealed on the tape. With multiplexing enabled, the tape drive does not 'shoeshine' or reposition between writes- data just keeps streaming, the drive keeps on spinning.
Disk has no such 'shoeshing' issues. Images are laid out in one contiguous stream of data, and restores are then single streamed as well.- In 6.5.5 there is a new option called "Maximum I/O streams per volume" if you are using SLP. You can read more in the Best practices for configuring NetBackup with Storage Lifecycle Policies
There is really no options to tune for the Basic Disk Storage Unit other than "the maximum job count".
If you have performance problems restoring form disk storage units - check the fragmentation level !!!
