Re: Slow rsync speed between usb drives
- I'm sorry I don't buy it.
I regularly get 3.0+MB/s (quoting rsync's --progress) between slugs with two hard-drives each. All four of my slugs are de-underclocked, and all of their hard drives are externally powered. I started with Maxtors but lately use internal harddrives upended in BlacX.
I did have compression enabled once, because I am silly, and the speed dropped into the KB-ish range. (Compressing compressed files only expands time...)
--- In firstname.lastname@example.org, "Mike (mwester)" <mwester@...> wrote:
> docbillnet wrote:
> > Hello,
> > I just purchased a couple of NSLU2 from tigerdirect.ca, and I have
> > followed the instructions for installing Linux on one. Overall, it
> > seems to be working well, especially since I cut the resistor.
> > However, I wanted to backup data from three 500 GB drives to a 1.5 TB
> > drive. However, when I used the --progress option with rsync, it
> > reported the transfer speed is 2.0 MB/s. After a quick back of the
> > envelope calculation, I concluded it will take 8 days to copy my data
> > from the three drives.
> > So, I shutdown the NSLU2, and plugged the same drives and USB hub into
> > my laptop. I issued the same rsync command, and my transfer rate is
> > 20 MB/s.
> > Is this a typical transfer speed with an NSLU2? If not, how do I go
> > about determining the problem and speeding up the transfer? From what
> > I've seen in this forum, I would expect a transfer speed between
> > drives of about 6 MB/s, but I can't be certain since the messages were
> > all related to how long it took to transfer files between a usb drive
> > and the network. Perhaps, the USB bus is much slower when it is both
> > reading and writing at the same time. Or perhaps rsync has too much
> > overhead, and I need to use a different program to copy data.
> > Bill
> What firmware did you install?
> How are the drives mounted (can you provide the output from the mount
> What exactly is the rsync command you issued?
> Mike (mwester)