deloptes wrote: > Dan Ritter wrote: > > > USB2 disks are good for about 25MB/s. > > > > Where do you have those numbers? > > USB 2.0 standard can theoretically transfer data at a very high 480 megabits > per second (mbps), or 60 megabytes per second (MBps) [for example in > wikipedia).
Yes, that's the theory. In years of running several USB 2.0 attached disks, I found that they were actually good for about 25MB/s long-term. Bursts to 37MB/s were not uncommon. The USB mass storage protocol forces a queue depth of 1: one request, one response, nothing else until it's done. The OP's 4K writes will be particularly badly performing. -dsr-