I use Robocopy a great deal to copy stuff from corpnet in a reliable way onto my laptop. One huge advantage of robocopy is that you can set it to copy in restartable mode, and if the network connection fails, it can take off from where it got to. Therefore, I can start copying something while in the office, suspend my laptop, come home, fire up the VPN and it continues. However, I’ve been copying down several gig of data yesterday and last night, and I noticed on my broadband performance monitor for ISA, I wasn’t getting anything like the full bandwidth being used.
A bit of a finger in the air approach, but it was generally noticable that the lowest performance is on files being copied less than 100K. This isn’t surprising as it has to seek to the next file frequently. Best performance comes on multi-megabyte files – again, not surprising as it flies if there’s no “seeking”. Fortunately, the files I’ve been copying handily fit into three directory sets with generally one of three names in the top-level directories – “Ethernet”, “WLAN” and “Video”. (It probably won’t be hard to work out what I’m copying down now 🙂 ).
I found it best to run up three instances of robocopy in three command prompts and use the /xd option to exclude directories. Hence:
- robocopy \\server\topleveldirectory . /s /xd *video* *ethernet*
- robocopy \\server\topleveldirectory . /s /xd *video* *wlan*
- robocopy \\server\topleveldirectory . /s /xd *ethernet* *wlan*
This increased the throughput for me by a good 50K per second and saved me a lot of time. Obvious, but nice to know.