[TriLUG] copying files

Jeff Schornick jeff at schornick.org
Fri Jun 22 11:39:21 EDT 2012


>> just doing an fstat() (or similar) on the other end?
>
> following Alexy's comment, I see that several RTT's are involved. However
> I'm still not transferring cdimage.iso just the timestamps etc

Right, but we're talking about 1000s of files.  So your overhead to
"collect the timestamps" is many orders of magnitude slower than using
rsync in the more traditional sense.  Such that if you latency is high
enough, it could easily eclipse your overall sync time.

Rsync is not optimized to be run against a filesystem that appears to
be local (nfs, sshfs), but one which incurs latency on each read
associated with a remote machine.

If I'm reading you right, it appears you're still mounting some sort
of network filesystem from "far away".  Don't do that if you plan on
using rsync to sync many files.  Let it do what it does best, where it
calculates each of its file lists on the respective machines.

If you're still getting huge sync times after that, it may be worth
getting some performance metrics on the various aspects of each
system.

  - Jeff



More information about the TriLUG mailing list