Network Speed Drop Offs

[Drezha]

Been playing with OpenMediaVault at home this weekend and I’m trying to figure out where the speed drop I’m getting is coming from.

Moving files around, I end up getting graphs that look like this:

Consistent speed at about 60-80MB/s until a point and then speed drops dramatically.

These are large single files, coming from from my Synology NAS to my OpenMediaVault machine. In fairness, it is being written to a USB stick on the OMV machine but not sure why it’s suddenly dropping like that.

Any ideas? I can only assume it’s filling a cache or something and then slowing down, but I can’t quite figure it out.

"Everything looks interesting until you do it. Then you find it’s just another job" - Terry Pratchett

[Tippon]

Have you tried copying it from the NAS to the computer first?At least that will rule out either the network or USB speed

[Ed P]

Typically you get that sort of curve during the period that the pc is writing from ram disk to file.  During this period nothing is being ‘transferred’, but a lot of final disk i/o is taking place. Looks to me that you have an efficient multi-threaded file copy program and large (couple of gigs?) ram buffer to write out.

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