Re: [Duplicity-talk] Using -z option in ncftpput

[Pascal Levasseur]

Hello,

I have done a test of the resume transfert feature of ncftpput with a
full backup to try to mitigate the impact on backup time of a very
unstable ADSL.

Short Version : 

        - It works very well on a set of 6 Gb of files (29 hours on a 5
        Mb / 512 Kb ADSL link),
        - The ncftp and the remote ftp server succeed in resuming
        transferts,
        - Duplicity dont complain;
        - Duplicity verify find no differences between the local files
        and the one who have been backup.    


Long version :

        - Modification of Duplicity
        
                * Patch of the file ftpbackend.py of Duplicity 0.5.17 to
                insert the -z option in the command string of ncftpput.
                * "python setup.py build" then "python setup.py
                install". No complain from Duplicity. 
                
                
        - Test of the resume function :
                 
                * 6 Gb of files to backup,
                * Total time of backup : 29 hours,
                * Set 206 and 207, transmitted without disconnection,
                have been timed at 7'30",
                * The ADSL link has been manually disconnected at 7'00"
                during set 208 "attemp #1" transfert,
                * The ADSL link is reconnected after 30 seconds,
                * The ADSL Modem re-sync,
                * Duplicity recover at "attemp #3",
                * Successful transfert of set 208 during "attemp #3"
                within 40 seconds after recovery of duplicity, showing
                the resuming of the ftp transfert.


        - Test of the backup :
        
                * The verify fonction of duplicity has been used to
                check all the backuped files with the original files.
                * Duplicity find no differences in files.
                
                
        - Environment :
        
                * Debian version 5,
                * Duplicity version 0.5.17,
                * ncftp  version 3.2.1,
                * Unknown ftp server software (hosted by Globat),
                * Ipcop Firewall version 1.4.21,
                * Orange ADSL 5 Mb down / 512 Kb up ADSL link,
                * ADSL very unstable with a lot of sync loss,
                * IP address changed each time the ADSL resync.

Temporary conclusion :

        * Is somebody interested in doing more test to verify my
        assertions ? 
        * May I ask for a "--ftp_resume" option in a future release of
        duplicity ;)


Pascal Levasseur


Le jeudi 21 mai 2009 à 06:13 -0500, Kenneth Loafman a écrit :
> It should work, but I've never tested it.  Let us know how it goes.
> 
> ...Ken
> 
> Pascal Levasseur wrote:
> > Hello all,
> > 
> > I would like to know if I can use the -z option (resume transfert) in
> > the ncftpput command used by Duplicity without any bad side effect(s) ?
> >