Hello Etienne, thanks for your reply. On 22/06/2019 16:35, Étienne Mollier wrote: > Jerome Benoit, on 2019-06-22: >> How can we check that a compressed file is rsyncable ? >> >> In fact I would like to know if tarball compress with plzip >> are rsyncable ? > > Good Day, > > If by "rsyncable", you mean "can be transferred by rsync", then > yes, like most files. :) Aaah ! > > If you wonder if the delta-transfer algorithm will be in use, > although I have not tested directly plzip, chances are the > compression will not enable it. I was refering to the long option --rsyncable of gzip(1). So, in fact the keyword I was looking for is delta-transfer . > > > If you wish to assess the efficiency of the delta-transfer, use > the option "--stats". At first transfer of the current source > code of rsync, repacked: > > $ rsync --stats -a rsync-3.1.3.tar.xz 192.168.1.101: > > Number of files: 1 (reg: 1) > Number of created files: 1 (reg: 1) > Number of deleted files: 0 > Number of regular files transferred: 1 > Total file size: 676,984 bytes > Total transferred file size: 676,984 bytes > Literal data: 676,984 bytes > Matched data: 0 bytes > File list size: 0 > File list generation time: 0.001 seconds > File list transfer time: 0.000 seconds > Total bytes sent: 677,262 > Total bytes received: 35 > > >>>>>> sent 677,262 bytes received 35 bytes 43,696.58 bytes/sec > total size is 676,984 speedup is 1.00 > > Then I add an empty "toto" file, repack, and see changes: > > $ rsync --stats -a rsync-3.1.3.tar.xz 192.168.1.101: > > Number of files: 1 (reg: 1) > Number of created files: 0 > Number of deleted files: 0 > Number of regular files transferred: 1 > Total file size: 677,000 bytes > Total transferred file size: 677,000 bytes > >>>>>> Literal data: 677,000 bytes > >>>>>> Matched data: 0 bytes > File list size: 0 > File list generation time: 0.001 seconds > File list transfer time: 0.000 seconds > Total bytes sent: 677,278 > Total bytes received: 5,015 > > >>>>>> sent 677,278 bytes received 5,015 bytes 454,862.00 bytes/sec > total size is 677,000 speedup is 0.99 > > In the case of tar archive compressed with XZ's LZMA2, the delta > transfer is not in use, the whole file is resent. (The > bandwidth increase here is most likely related to the drive > spinup time at first transfer, the target was a low end laptop.) > > When delta transfer is in use, given a file with the following > properties at first transfer : > > $ rsync --stats -aSH rsync_3.1.3-6.dsc 192.168.1.101: > > Number of files: 1 (reg: 1) > Number of created files: 1 (reg: 1) > Number of deleted files: 0 > Number of regular files transferred: 1 > Total file size: 1,877 bytes > Total transferred file size: 1,877 bytes > Literal data: 1,877 bytes > Matched data: 0 bytes > File list size: 0 > File list generation time: 0.001 seconds > File list transfer time: 0.000 seconds > Total bytes sent: 1,993 > Total bytes received: 35 > > >>>>>> sent 1,993 bytes received 35 bytes 1,352.00 bytes/sec > total size is 1,877 speedup is 0.93 > > append a line with "toto" at the end of file, resend, and you > should see a non-zero value for matched data: > > $ rsync --stats -aSH rsync_3.1.3-6.dsc 192.168.1.101: > > Number of files: 1 (reg: 1) > Number of created files: 0 > Number of deleted files: 0 > Number of regular files transferred: 1 > Total file size: 1,884 bytes > Total transferred file size: 1,884 bytes > >>>>>> Literal data: 484 bytes > >>>>>> Matched data: 1,400 bytes > File list size: 0 > File list generation time: 0.001 seconds > File list transfer time: 0.000 seconds > Total bytes sent: 613 > Total bytes received: 53 > > >>>>>> sent 613 bytes received 53 bytes 1,332.00 bytes/sec > total size is 1,884 speedup is 2.83 > > See what it gives when you test transfers of you plzip archives. Thanks for the hint. I will give it a try once I have before me. > > Happy hacking, > -- Jerome BENOIT | calculus+at-rezozer^dot*net https://qa.debian.org/developer.php?login=calculus@rezozer.net AE28 AE15 710D FF1D 87E5 A762 3F92 19A6 7F36 C68B
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