Re: [Duplicity-talk] Duplicity, scp, fc5, backend exception problem

[Bill Wraith]

On 11/19/06 10:28 AM, "Bill Wraith" <address@hidden> wrote:

>... The errors vary somewhat, but
> the basic theme is a backend exception failure which appears to be the
> os.system call to scp a file from the repository to local or from local to
> repository.
>...However, I then tried backing
> up to a server on my LAN, which is 100Mbps and still have frequent backend
> exception errors with scp commands moving a repository file to or from local
> tmp file. 
> In verify mode, the scp also fails.
> 
> Any advice on how to resolve this problem or anyone familiar with problems
> using duplicity on fc5?

By the way, fc5 was recently updated to kernel 2.6.18 with all updates,
duplicity is v4.2 installed from tar.gz.

I added the following hack to backends.py around line 142, and it seemed to
successfully do a very large verify that has failed consistently in the
past. There was one error message, presumably from a failure that was
retried this time. The hack and the error are listed. Are there parameters
in sshd_config on the server or ssh_config on the client that would result
in a more forgiving scp/sftp connection, or are there networking parameters
that might make the scp/sftp/sshd communication less likely to fail? This
failure may happen only once in verifying or backing up a 6GB file.

def run_command(self, commandline):
                """Run given commandline with logging and error detection"""
                log.Log("Running '%s'" % commandline, 5)
                if os.system(commandline):
                        if os.system(commandline):
                                raise BackendException("Error running '%s'"
% commandline)

(In other words, just try one more time)

The error that showed up once, which was probably what would have failed the
entire backup before was:

ssh_exchange_identification: Connection closed by remote host

As the scp was redone successfully, the verify on a large directory (about
6GB) went on to complete successfully and showed no errors.

Thanks, Bill Wraith