On Fri, Aug 29, 2003 at 03:22:59PM +1000, Martin Pool wrote: > On 28 Aug 2003 jw schultz <[EMAIL PROTECTED]> wrote: > > > On Thu, Aug 28, 2003 at 12:51:16PM +0300, Sviatoslav Sviridov/Lintec > > Project wrote: > > > > > > Sorry for direct reply, but mail server at samba.org blocks my > > > messages. > > Can you please tell me exactly what error you get, and preferably > forward to me an example bounce? If sending it to me does not work > either then please send it to jw and he can forward it to me.
Will do. > > > BTW, is there patch for bzip2 that adds --rsyncable option? Or may > > > bw someone working on it? > > > > I don't expect so. > > > > The --rsyncable patch for gzip uses file content patterns to > > reset the compression algorithm so that even if you insert > > or delete data early in the file rsync can still find > > matching blocks. Look at the patch for further details. > > > > As far as i can tell from the manpage bzip2 is compresses > > data in fixed size blocks with a reset on block boundaries. > > This means that it is moderately rsyncable as long as you > > never insert or delete data. You can change early data > > without affecting later blocks but only if the offsets of > > later blocks remain the same. This does not lend it to an > > rsyncable patch. This does mean that bzip2 is good for > > block oriented data such as database tablespace files and > > for files that are appended to but bzip2 would be > > undesireable for text, word processor, tar and other less > > structured files. > > I think this is correct. > > You could naively simulate this by just splitting your file into 900kB > chunks before compression. There would also be a tradeoff between rsync efficiency and compression rate in using smaller blocks via the bzip2 options -1 .. -8. All dependant on the file modification patterns. Given such large block sizes in bzip2 rsync block allignment is unlikely to be an issue. -- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: [EMAIL PROTECTED] Remember Cernan and Schmitt -- To unsubscribe or change options: http://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html