direct IO, IO throttling

[Aurimas Mikalauskas]

Hi there,

I've been googling around and yet could not find if there's a decent
solution to avoid OS cache while copying files with rsync. It would be
good if that worked both on client and on server side.

If not some rsync patches (or features in upcoming releases), maybe
you know of some library that could be ld_preload'ed to do this?

Another thing I'm looking for is a way to limit number of IO
operations. --bwlimit option is great when you want to save on network
bandwidth, but when you are doing a backup of high number of small
files (like email maildirs), rsync does a lot of IO operations which
exhausts IO subsystem with relatively small throughput.

Some preloaded library could do that as well I guess, but I couldn't
find anything like that so far and before working out something, I
wanted to see if there's something invented already..

Thank you in advance!