On Mon, Apr 11, 2011 at 4:32 AM, Matt Willsher <[log in to unmask]> wrote:
> On 11 April 2011 12:08, Federico Alves <[log in to unmask]> wrote:
>> The limitation is not my hardware. The servers are both Dell R900 with SAS
>> disk arrays. Also, from a Windows virtual machine, inside the same server,
>> I get around 400 MB speed using FTP transfer, windows to windows. There
>> must be a different way to do this from Linux.The files are sparse files,
>> and I need to keep them that way, that's why I use rsync.
>
> Have you tried rsync server on the remote side? I've always found
> transfers over SSH to be rather slower than I'd like although 22Mb is
> slower that I'd expect. It comes down to a process of ellimination so
> try and get SSH out of the equation and see if that helps. If not,
> check disk performance with iostat (part of the sysstat package)  and
> make sure there isn't a problem with queues or disk utilisation there.
> Check the network for problems - try a different protocol and some
> dummy files, make sure there isn't packet loss via netstat.
>

If this helps, you might also review your rsync setups. Sending lots
of distinct rsync requests, and thus lots of newly established SSH
setups, causes considerable startup overhead for each connection,
especially if the machines are not set with valid reverse DNS. (The
SSH server looks up the reverse DNS of the connecting client to log
the hostname of the connection: this is only really disabled by using
'sshd -u0' in the init script, instead of 'sshd'.)