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Why is backup using only 1 thread?

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I have 8 logical CPUs in my computer. Older versions (like ATI 14) use to use all CPU cores.

Obviously since it's using 1/8 the threads it is 8x slower...

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Hello pro-logic,

Thank you for sharing your findings.

You may have noticed that only 1 CPU core is used during preparation stage, when Microsoft Volume Shadow Copy (VSS) is working and preparing disk snapshot. That corresponds to "Calculating time remaining" status on progress bar. When real data transfer begins and "calculating time remaining" label disappears, if you look at CPU cores usage, you will see that all they are equally in use.

If you were doing file-level backup you may have noticed increased time at preparation stage in 2016 version because even for files/folders backups 2016 version requests Microsoft VSS to prepare a disk-level snapshot that it uses later during data transfer.

As we did not interact with VSS at all in 2014 and all older versions, it may have looked faster you specifically because of extra minutes at backup preparation. However, if you compare overall time required to created complete backup with 2014 and 2016 versions, 2016 could result to be even faster.

Regards,

Slava

Hi Slava,

Thank you for your reply and description. However this is not how it's working in real life. It uses only 1 core throught the "Calculating time remaining" and after the label disappears.

Through all parts of the backup process only 1 core is in use. 

 

Pro-logic.  What is the affinity set for on your system with this application?  By default, on my Windows 10 x64 Pro system shows affinity set to run on all 4 cores. Running a backu shows all 4 logical cores of my i5 chugging along as well.  

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The cpu affinity is set to all 8.

I have attached screenshots of the CPU use and Disk use.

For the record it's backing up from a RAID 0 to a WD Red. So throughput should be a lot more then 4MB/s.

 

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4Mb/s is really slow.  Is this locally attached or a NAS device?  Even a USB 2.0 drive with a 5400RPM drive should be getting closer to 20Mb.  I typcially only see low throughput like that when backing up to a network share where there is a bad connection (wireless?).  I'm at a loss for why your system would only be using 1 core as I cannot reproduce the scenario on any of my home systems.