Dramatic Performance change while copying large file

[jeffreywhunter]

Wondering if anyone has an idea why performance would suddenly drop off like this.  Large 40gb single file transfer.  Copy initiates, runs at 104mb/s for 5 or 6 minutes, then drops off to 15mb/s.  A parity check was running (in the screenshot), so I thought the parity check might have hit the disk the file was sitting on.  So I stopped the parity check, but no change.  Still 15mb/s or so.  Any thoughts?

 

Here's Stats from the gui

http://my.jetscreenshot.com/12412/20161003-jz4i-224kb.jpg[/img]

[CHBMB]

My guess would be caching

[jeffreywhunter]

Which Cache?  Its copy FROM the server, so the cache drive wouldn't be involved...right?

[CHBMB]

Disk write caching is a feature that improves system performance by using fast volatile memory (RAM) to collect write commands sent to data storage devices and cache them until the slower storage device (ex: hard disk) can be written to later. This allows applications to run faster by allowing them to proceed without waiting for data write-requests to be written to the disk.

 

While disk write caching may increase system performance, it can also increase the chances of data loss in case of power or system failures before the data from the write-cache buffer is flushed by writing the data to the disk.

 

From tenforums.com

[RobJ]

Another possibility, a fault in NIC offloading can cause that.  Take a look at Tips and Tweaks wiki page (use the Tips and Tweaks plugin).