All, I'm not sure this is on-topic, but at least I'm in cygwin when I notice the below:
I do a lot of large data transfers between USB drives. Often I get great speeds (70MB/sec or more). Sometimes it falls way off to closer to 20MB/sec with the same class of hardware. I experienced the "slow" transfer speed today, so I thought I'd ask if anyone knew a way to resolve it? The PC I'm running on is spec'ed for data processing so a 6 core (12 thread) setup with 128GB or RAM. No significant data processing is going on. Basically the machine is currently dedicated to running rsync (as below). I have 2 USB drives hooked up. Both are USB-3 and should be able to do 70MB/sec with no issue. Neither drive has any unrelated I/O going on that I know of. (I don't see any in the Windows Performance Monitor.) I have a folder with almost 200 4GB files ( 750GB total and all the files are large). I'm using "rsync -av" to copy files from the source to the destination and the folder on the destination started out empty Using Windows "Resource Monitor" I normally would see both drives hitting over 70 MB/sec. Today I'm seeing the source drive jump all the way up to 125 MB/sec or so, but the destination is down around 20 MB/sec When the 4GB source file completes reading, the source drive basically goes idle for a while until the file is written out. Then the source drive jumps back to 125 MB/sec until it finishes reading the next file. The destination drive on the other hand is stuck down around 20 MB/sec. I really don't think this is caused by slow hardware. Could the destination drive be dropping down to USB-2 mode? === And now that I've written up the above, the system has returned to a more normal 75 MB/sec consistently on the output drive. I'm still curious what might be going on. As I say I move a lot of data around as part of my work, and much of the time it is big groups of either 1.5GB or 4GB files. Thanks Greg -- Greg Freemyer www.IntelligentAvatar.net -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
