scp a little slow? windows vm ubuntu and mac leopard

Question

I am running ubuntu under VMware. I connected my USB drive directly to ubuntu instead of through windows XP and i started transferring files from my mac leopard to ubuntu/usb HD

Most of the time the speed is 2.8MB/s. The scp command i used was something like

scp "name here@lanIP:./" ./

I dont want to stop the transfer to check. (.bash_history didnt show me my command)

Is this right for a transfer speed? my laptop and mac are connected via ethernet cable. The network should be 100mbp which makes me think i should get less then 12mb. Maybe 8MB per second. 2.8 seems slow. I am transferring >22gb so a slow transfer will make me suffer. By my time it will take roughly 3hours to complete.

Answer 1

Your speed is quite similar to speeds I've seen on other 100Mbps networks with SSH. The transfer speed seems to depend alot on OS you are using, and not that much on the available CPU speed. On one network all transfers between PCs running Debian or Ubuntu Linux had 3MB/s speeds, but when I was using SCP on a Mac OS X server, I always got over 6MB/s. Also file transfers from a Xen server (which is running CentOS variant I think) also gave me higher speeds. Only time I've gotten faster transfer speeds with Debian Linux and scp are when I've copied data from one Xen virtual machine to another on the same Xen server, then I would get 20+MB/s speeds.

With Samba shares, you usually can get to 50Mbps or so, and If you want speed easily, I would recommend setting up a FTP server, with that I usually can get 90Mbps easily, even from a Windows machine.

Answer 2

scp is completely inefficient with lots of small files. I suggest using rsync instead. rsync can use ssh for transport, and will notice your already transferred files and save bandwidth.

Answer 3

As Tobu mentioned, SCP is inefficient when copying lots of small files. A common trick is to channel a tar stream through SSH. See: http://www.thingy-ma-jig.co.uk/blog/03-09-2008/using-tar-and-ssh-improve-scp-speeds

You can also bump up the speed a little by using faster ciphers like blowfish. example:

tar czf - /path/files-to-copy | ssh -c blowfish user@remotehos tar xzf - -C /path/to/destination