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Question

how to control ondemand backupset multistreaming

  • September 4, 2025
  • 2 replies
  • 18 views

downhill
Byte
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Hi,

I have been using some custom ondemand backupsets for about a year to essentially spool (if that’s the correct term) content from some NFS paths to tape. Each backupset has one subclient, one directive obviously, and one content file which each day is updated to contain 2 directories. What I can’t seem to find is how the number of readers is set or limited. Did readers disappear and replaced by the folder level multithreading? If so, then I think I can figure it out. Basically my read on this is (historically) each path in a content file was “a stream” but in 11.36 the notes seem to imply each content file is a stream, either way, IMO with my configuration the job should be limited to 1 stream - Can a vaulter confirm? If this is the case then why do I see 4 streams for that “job” which should be technically limited to 2? Does the number of Network Agents factor in along with the Number of threads? I just don’t see where this is explained.

thanks!

2 replies

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Hi ​@downhill ,

Good day!

We need to check the number of data readers configured under Subclient Properties → Advanced → Data Readers.

If it is set to 4, then even with only 2 folders in the content, Commvault may split the subdirectories (based on size) and allocate up to 4 streams.

The number of Network Agents does not impact the number of streams, but it does help with network throughput.

Regards,

Sureshkumar S


downhill
Byte
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  • Author
  • Byte
  • September 10, 2025

Well, maybe in the old versions, but 11.36 has no such setting. It only has 

 

There is no setting for these either in the SC, schedule, or backupset to control it it appears. The documentation appears incorrect. A content file should be “a stream” which is not the case. A content file with 2 dirs spawns 4 readers regardless of that multi-threading setting - I’ve tried with it enabled and various threads, zero correlation. I don’t get it.