why rsync update large directory so slow?

[Fabian Cenedese]

At 14:22 24.11.2015, =?gb18030?B?t+fQzg==?= wrote:
>Hi:
>  I have a large directory with about 0 Milillion files in it to backup by network. Server and client both windows.
> 
>In order to make backup faster, I created many rsync intances with "-avvu" options. It seems worked, and only take about 5 hours to complete backup job. 
>When I restarted the client bat script, and expect very little time to complete backup, but it still cost about 3 hours. 
>It seems that concurrence makes no effect, I can not figure out what happend, the file checking is so slow?
>Does anybody encounted cases like this? Any help will be thankful.

If this is just one directory on one hard disk then the disk head has to
move constantly from one place to another to another to another for
each process. It's possible that it will run even faster if you have
just one process. On the other hand Windows will cache file info
in RAM so a second run could be faster then the first one. This
depends one your RAM, how much have you got? Have you tried
with just one process?

bye  Fabi