[PLUG] Ruminations on rsync

John Jason Jordan johnxj at comcast.net
Thu Feb 15 21:58:50 UTC 2007


Yesterday I was trying to fix OpenOffice.org and in the process I
stumbled across Grsync in Synaptic. It's a Gnome GUI front end for
rsync. I installed it to check it out. It didn't make a launch item in
Applications, so I launched it from the command line. Didn't seem like
a bad little app, so I decided to take it for a spin. I mounted my USB
procket drive, made a new folder on it, then told it to rsync ~/ to the
new folder, excluding one 14 GB folder that I didn't need backed up
(mp3s, that I have copies of elsewhere). The total to back up came to
9.8 GB. The USB dirve had about 40 GB free space. 

Rsync sent the CPU to 100% while it was working. It got to about 12%
and hung with the CPU at 100%. Actually, the command line said "core
dump," and then I saw that rsync was no longer copying files and that
the CPU was pegged at 100%. I waited awhile to see if the CPU would go
back to normal, but after ten minutes it was still at 100%. The red
light on the USB drive was still on also, so I unmounted it. After a
couple more minutes the red light went back to green and I pulled out
the plug. The CPU stayed at 100%. I ran top and couldn't see anything
running that shouldn't be. I also looked in System > Administration >
System Monitor, and didn't see any processes that shouldn't be there --
e.g., no zombie copies of rsync. I had started this right after
rebooting and had nothing else launched other than system stuff, so I
just shut the computer down and restarted. After restarting I remounted
the USB drive and noted that rsync had copied things to it -- there
were files in the new folder.

Now, I have been vexed for ages with rsync hanging or failing in the
middle of a job. I can copy the whole 9.8 GB in ~/ to the USB drive
with the cp command. And tar seems to work OK too. But rsync is flaky.
It will also hang if I try to rsync to a USB drive hanging on a Windows
2000 desktop over the ethernet.

A couple weeks ago I subscribed to an e-list for rsync. I note constant
posts from people about rsync hanging. I am slowly arriving at the
conclusion that rsync is not to be trusted, at least the version I have
available in Synaptic for Ubuntu amd64. At first I thought the problem
was in USB 2.0 on Ubuntu amd64, but the fact that it also hangs going
over ethernet tells me that that assumption is unwarranted. And the
fact that cp and tar work but rsync hangs tells me that the problem
must be in rsync.

Has anyone else enountered flakiness with rsync? Do my conclusions seem
logical? And if rsync is not usable for me, can anyone else think of a
simple backup solution for someone who needs to back up a laptop on an
irregular as-needed basis?



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