John,
gzip will report an error if it detects that the file has hard links, e.g.,
gzip bigfoo
gzip: bigfoo has 1 other link -- unchanged
Similarly, with bzip2:
bzip2: Input file bigfoo has 1 other link.
I thought about using a staging area, compressing the files there, and
then rsyncing between the staging area and its history. That process
was far too slow so I gave up. This requires a complete copy of the
target and rsync does not get to do any of its magic. Alternatively,
you could uncompress the last daily.0 into your staging area and then
rsync against that, but I did not try that.
What I do, instead, is try to squeeze out extra redundancy out of the
target collection of files using William Stearns' freedup.pl Although
rsync / rsnapshot create hard links where historic differences in a
given file are zero, there are often identical files in your collection
which can be hard linked together. You only need to do this with the
daily.0 after each rsnapshot run; the links among duplicates will
persevere across subsequent generations.
--Carl
Date: Mon, 23 Aug 2004 00:12:03 -0400
From: John Taylor <john < at > fcs.uga.edu>
Subject: [rsnapshot-discuss] idea for rsnapshot
Would it be feasible to compress files located in older snapshots, like
the weeklies and monthlies? Even if rsanpshot simply gzipped each file,
I think you could save on disk space. Or is this not true due to the
hardlinking of files?
-John
-------------------------------------------------------
SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285
_______________________________________________
rsnapshot-discuss mailing list
rsnapshot-discuss < at > lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/rsnapshot-discuss
