rsync - May 2013 - [Bug 9915] New: File stopped synchronizing during transmission

https://bugzilla.samba.org/show_bug.cgi?id=9915

           Summary: File stopped synchronizing during transmission
           Product: rsync
           Version: 3.0.9
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: major
          Priority: P5
         Component: core
        AssignedTo: wayned at samba.org
        ReportedBy: oswulf_chua at msn.com
         QAContact: rsync-qa at samba.org


We have currently trying to transmit data from one server to another using
RYSNC by synchronizing 2 folders. Occasionally, we noticed that the file stop
when in the middle of transmission (we can see tmp file created on the
receiving end) even through the file has completely written to the the folder
on the sending side. After a long while (7-30 minutes), it will complete
sending. We are not sure if the following is true, but if we start sending a
file to the same folder the such issue happen, the "hung" file will
resume
sending and complete immediately. The message file that we sent are usually in
the sizes between 1MB-4MB. For the time being, we are sending small-sized file
of 1byte to "trigger" and "hung" transmission. Below is the
arguments that we
are using

RSYNC_ARG="--log-file=$LOGFILE --chmod=a+rwx,g+rwx,o+rwx --exclude=*.tmp
--remove-sent-files --stats --ignore-times --whole-file -qr"

There is no data loss but we encountered a long delay in data transmission.

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https://bugzilla.samba.org/show_bug.cgi?id=9915

--- Comment #1 from Alvin <oswulf_chua at msn.com> 2013-06-10 00:10:02 UTC
---
For the time being, we are sending small 1byte message periodically to
"give a
push" to the "appeared to be hung" files over. This seems to work
temporarily
and we are hopping to have a fix for this issue. Let us know if this is a
configuration issue as well.

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On Wed, May 29, 2013 at 04:39:55AM +0000, samba-bugs at samba.org
wrote:
> https://bugzilla.samba.org/show_bug.cgi?id=9915
> We have currently trying to transmit data from one server to another using
> RYSNC by synchronizing 2 folders. Occasionally, we noticed that the file
stop
> when in the middle of transmission (we can see tmp file created on the
> receiving end) even through the file has completely written to the the
folder
> on the sending side. After a long while (7-30 minutes), it will complete
> sending.
>
> We are not sure if the following is true, but if we start sending a
> file to the same folder the such issue happen, the "hung" file
will resume
> sending and complete immediately. The message file that we sent are usually
in
> the sizes between 1MB-4MB. For the time being, we are sending small-sized
file
> of 1byte to "trigger" and "hung" transmission. Below is
the arguments that we
> are using
Are you sure it's not a network issue?  Have you tried swapping
cables?  Are there any interface errors on either end?  ifconfig will
show that, and you might also check linux sysstat.

It sounds like tcp packet loss.  Are you able to strace both rsync
processes when this happens?

Justin