[CentOS] How to speed up Rsync transfers

Fri Feb 22 17:06:17 UTC 2008
nate <centos at linuxpowered.net>

Dan Carl wrote:
> Is there a way to speed up rsync transfers?
> I tested the bandwidth with iperf (recommended to me in an earlier post &
> worked well)its as advertised by my ISP's around 740KB/sec.
> When I manually run my rsync script with the --progress switch the transfers
> are around 100KB/sec.
> I googled this and the only thing I found had to do with the TCP window
> which I understand to be the limiting factor. But if this is true how can I
> ftp stuff at 300KB/sec? (someone please enlighten me)
>
> I'm backing up jpg files and some days they add 5+GB of images.
> My goal was to backup the images nightly, but at the 100KB/sec rate that's
> not possible.

What options are you using with rsync ? Stay away from the  -z option
if your copying jpegs. That'll slow things down quite a bit. I have
no problem using rsync to copy at 20+MBytes/second with the default
tcp window size on gigabit networks(using rsync over SSH). And I
can achieve ~700kByte/s on a 10Mbit link over a VPN between two sites(
about 40 miles apart), again, default tcp settings across the board.

Also note that some ISPs, such as Comcast have features built into their
services that provide an initial "power boost" for a few seconds to
speed up file transfers, then are quickly throttled down to "normal"
levels. In this case your bandwidth test with the ISP may not of lasted
long enough to show your "true" long, sustained available bandwidth.

The options I use:

rsync -ave ssh (local file) remote_server:(remote file)

or rsync -ave ssh --progress (rest of command)

nate