Wednesday, June 27, 2012

Did you know that the Robocopy that with comes with Vista+ supports multithreaded copying?

TechNet Magazine - Perform Multithreaded File Copies with Robocopy...

"Windows included the popular Robocopy utility, which offers powerful file copy capabilities in a command line interface. Robocopy is included in Windows 7 and features a new multi-threaded copy option. To perform a multi-threaded copy, you use the new /MT[:n] switch, where n indicates the number of threads to be used. By default, n is 8 when you use the /MT option, and can be any value from 1 to 128.

Note that the multi-threaded option is not compatible with the /IPG and /EFSRAW options." [GD: Post leached in full]

Stephen Foskett, Pack Rat - Robocopy: Better, Faster, Stronger


Dead or alive, you’re coming with me!

I tried out the new /MT option on a Core 2 Duo laptop and was surprised by the dramatic improvement in copy performance. Copying my entire “Program Files” directory took well over a minute without multi-threading, but simply specifying “/MT” at the end of the command reduced a second copy to a different directory to about 20 seconds. Using “/MT:32″ was blazing fast – easily less than 15 seconds. I repeated the first single-threaded test again and watched it dawdle along, taking over a minute again to finish.

Microsoft suggests that multi-threaded Robocopy helps with network throughput as well. I tried a series of copies between two Windows 7 machines over Wi-Fi, to simulate a slow network. Although single-threaded Robocopy was able to saturate the network with large files, it really slowed down (thanks to latency) once it hits a patch of smaller files. Multi-threaded Robocopy was more capable of maintaining high throughput once smaller files were encountered, with a 32-thread test keeping the link at maximum pretty much the entire time. Again, a noticeable improvement.



This is one of those things that I've found that most robocopy users don't know about... If you robo you should /MT too (and redirect the log too)...

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