[nSLUG] Re: rsync questions

Mike Spencer mspencer at tallships.ca
Wed Feb 23 16:07:15 AST 2011

me> The -a switch seems to be doing all of that that I need.  All
me> files are owned by my primary username so maintaining owner is
me> default.

Daniel Morrison <draker at gmail.com> replied:

dm> You will get an non-fatal error message if rsync fails to set
dm> ownership. This might happen, for example, if you are careless
dm> (who isn't sometimes) and create a file in your home directory as
dm> root and forget using chown to set the ownership appropriately.

Ah, yes.  Occasionally, when tcpdump shows some interesting,
unsolicited incoming packets, I get a root-owned log in ~.  My backup
script should do a find(1) for such files before proceeding with

dm> If either CPU is very slow, the encryption speed could be the
dm> limiting factor.

What about running rsync --rsh=/usr/bin/rsh on a trusted LAN?
No encryption overhead.

dm> 600 kB/s is 5Mbps (megabits/s), which is slightly more than half
dm> the maximum bandwidth of a 10Mbit link. If you're at 10 Mbit then
dm> this might be about as fast as you can get. However almost all
dm> routers are 100 Mbit, in which case it seems abysmally slow.

My DLink 713P router claims to support 100Mbps but doesn't. I have to
force 100Mbps NICs in the computers to 10Mbps with ethtool or the
computer never establishes a working connection to the router.  I
cling to the old router because I don't want to hassle with adapting a
USB print-server port to my perfectly good parallel/Centronics laser
printer.  (Is that so hassle-free that I shouldn't let it deter me
from buying a new router? Or not?)

The slower LAN speed is usually not a problem.  Last night's initial
backup of ~ was, I eventually noted, tediously prolonged by a 5G video
file that should not have been in the ~ tree.  More than twice the
size of all other files together.  Ho hum. Memo to self: Backup script
must check for huge files that don't belong.

dm> Your LAN is as secure as the weakest system on it.

I am reminded of a scene in The Man in the Iron Mask (1998 movie)
where Aramis says,

    The King had ordered me to find the secret general of the Jesuits
    and kill him.  But, you see...[lowers voice]........*I* am the
    secret general of the Jesuits.

I'm probably the weakest system on my LAN. :-)

dm> Sounds like you're on top of things though.

More or less.

dm> Anyway, experiment a bit and see what happens....
dm> Hope you enjoy your time with rsync :)

Yes, thank you.

- Mike

Michael Spencer                  Nova Scotia, Canada       .~. 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

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