Local disk to disk Rsync taking an hour longer than disk to remote

[Matt McCutchen]

On 7/16/07, W Smith <digitalmagnets at googlemail.com> wrote:
> Back in June I posted about the trouble I've been having backing up
> some local directories and I'm no further ahead than back then.
>
> Link for that discussion:
> http://lists.samba.org/archive/rsync/2007-June/017882.html
>
> In summary: I'm copying nearly a million small files from the main
> disk in a server to another disk in the same machine.
>
> Still on this server, but at a different time, I am backing up the
> same million files to a remote server which is completed massively
> quicker and I just can't get my head around why this should be.

Let's see if we can solve the problem for good this time...

- First, as a sanity check, please send the command lines for both rsync runs.

- To rule out disk I/O being the bottleneck in the local run, you
could try the same run with "cp -a" instead of rsync.

- Is rsync stalling in the same way you described before (
http://lists.samba.org/archive/rsync/2007-June/017885.html )?  If so,
please send straces for the sender, the receiver, and the generator so
we can begin to investigate.

- In the meantime, you might like to try the current CVS rsync both
with and without incremental recursion to see if it works any better.

> At this stage I'm close to giving up and am considering forgetting
> local backups and getting another server to have two remote backups
> instead, which wouldn't be a bad thing.

Have you tried doing rsync over ssh to localhost?  That is easier and
might have the same effect.

Matt