[CentOS] network copy performance is poor (rsync) - debugging suggestions?

Thu Jan 29 13:13:00 UTC 2015
Eero Volotinen <eero.volotinen at iki.fi>

2015-01-23 11:44 GMT+02:00 Götz Reinicke - IT Koordinator <
goetz.reinicke at filmakademie.de>:

> Hi,
> I do have two centos 6.6 servers. With a "performance optimized" rsync I
> get an speed of 15 - 20 MB/s
> The options I use are:
> rsync -aHAXxv --numeric-ids --progress -e "ssh -T -c arcfour -o
> Compression=no -x"
> If I copy files by smb to/from the servers I do get 60 - 80 MB/s, a dd
> (r/w) on the storages attached gives 90 MB/s on the 1Gbit ISCSI (Source
> Server) and up to 600MB/s on the 10Gbit ISCSI (Destination Server) storage.
> Both servers have plenty of memory and cpu usage looks low.
> Currently we dont use jumbo frames. Network over all usage is moderate
> to low. There are no special sysctl tweeks yet in use.
> As mentioned, I'm confused that even with SMB I do get 3 to 4 times
> better performance.
> Any hint and suggestion to track that problem down is welcome!

Problem is ssh, do not use it or apply hpnssh-patches:
http://sourceforge.net/projects/hpnssh/ to improve network performance