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rpandey's avatar
rpandey
Level 3
10 years ago

Best practice “Maximum I/O streams per volume” with Disk Pools

My backups are failed with below error -    awaiting resource CSD-SYD-STU-PD Reason: Maximum I/O stream count has been reached for disk volume, Media Server: ABC1257,       Robot Number: NON...
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  • sksujeet's avatar
    sksujeet
    10 years ago

    you can use process monitor or any 3rd party tool at the time of backup to see the read/write iops on the disk to see if it can take any more load on this or it is already taking too much load.

    If you read through above 2 posts you should be able to sort this out.

  • Nicolai's avatar
    Nicolai
    10 years ago

    Be careful not to overload SATA disk. They have limited amount of I/O per spindle.

    Also the number of spindles has a impact on performance. 20 spindles will be able to drive better performance than only 5.

    This is why there is no "general best practice", it all comes down to the disk subsystem, type of disks, number of spindles and RAID type.

Marianne's avatar
Marianne
Level 6
10 years ago

There is no 'best practice' for this value.

The amount of concurrent writes that can be handled depends on media server specs and lun layout on the disk volume.

You can try to increase the value in small increments - e.g. 2 per night.
Carefully monitor resources on media server with increased streams.
At the point where you see the mediaserver 'battling', go back to previous setting.

It may be time to stand up a new media server...

Have a look at this featured post:

Updated NetBackup Backup Planning and Performance Tuning Guide for Release 7.5 and Release 7.6