On Tue, Jul 13, 2010 at 5:19 PM, Mike Miller <mbmiller+l at gmail.com<mbmiller%2Bl at gmail.com> > wrote: > > > Thus, this... > > External HDD #1 --> remote machine --> External HDD #2 > > ...was about twice as fast as this... > > External HDD #1 --> External HDD #2 > > There's something very wrong with a system that works that way. If I had > enough space on my internal HDD, I'd do this and probably get even better > results: > > External HDD #1 --> Internal HDD --> External HDD #2 > > > Another crazy thing is that it must have been really killing my CPU > because I could hardly do anything else while the drive-to-drive USB > transfer was active, but programs like "ps aux" and "top" (both of which > literally took minutes to launch) seemed to show that almost nothing was > happening. Why is that? > I think this is likely a case of bus-contention. Especially if the reads and writes were being sent through the same bus/controller. I've had similar issues when doing things with USB devices. Also were you doing your copies at the file system level (cp or drag-and-drop) or at the block/device (dd) level? If at the file system you're incurring overhead in allocating space within the file system and updating the filesystem structures. Depending on how many files you have - that can add up to a significant amount of overhead. -Rob > > Mike > > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.mn-linux.org/pipermail/tclug-list/attachments/20100713/dcff6f57/attachment.htm