Zbip2 Size limitatations ?

[Franck Y]

Gene,
I ll try tonight the gzip contribution, for all my file. (mostly
Office documents).

I have a big forder wich is 11 Go without any compression. With bz2 it
compress to 4.1 Go which is nice because it fit in a DVD
With gzip it take 4.8Go, and i have to take another dvd or Cd to burn it...

I cannot tolerate neither a failure rate even if it's only 0.01 %. All
of this folder are extermely important.

Ig gzip is more robust, i do not have another choice...

Franck

On 12/31/05, Gene Heskett <gene.heskett at verizon.net> wrote:
> On Friday 30 December 2005 23:56, Franck Y wrote:
> >Hi everyone,
> >
> >I make several backup with bzip2, it seems that he has the better
> > compression.
> >
> >I do my backup like this for several folders.
> >
> >tar cvf - /home/data/ | bzip2 -9 > /backup/data.tar.bz2
> >
> >When i test the archive with bzip2 -t archive.tar.bz2, everything is
> >correct when the archive is under 1 Go. But i get CRC error when it's
> >upper ....
> >
> >
> >Has anyone experience this ?
>
> No, other than I've also heard that bzip2 has problems with source
> streams above 2GB, which would explain the effect your are seeing.
>
> As an amanda user myself, it seems rather foolish to make a single
> backup file that big considering what you have lost if its
> unrecoverable, and bz2 stuff can be entirely too sensitive to the
> medium its on.  Its demonstrated that to me on many occasions.
>
> "gzip best", OTOH, is considerably more robust in my experience, and
> faster in the compression cycle than bz2.  And, when you have a good
> backup manager, the individual files can be made fairly smallish so
> that each file in the archive remains a manageable size.  My amanda
> disklist has 44 entries scattered over 2 machines because I've
> purposely made each entry only one, under a gigabyte of raw data,
> directory tree.  Having smallish files means amanda can more easily
> manage the storage to make maximum use of the tape it is allowed to
> use each night, and I've often filled the tape to 98% capacity without
> ever hitting an EOT from the drive.  With a mixture of entries that
> compress, and those that aren't (because they already are, like rpms &
> tar.gz's etc) gzip can routinely reduce 16GB of raw data into 6GB on
> the tape, so I don't consider the better compression performance of
> bz2 to be an advantage other than in the eye of the beholder.  Storage
> today is cheap, use what works more dependably rather than that which
> may work slightly better, but only 99% of the time.  For backups, a 1%
> failure rate is unacceptable to me.
>
> >--
> >Franck
>
> --
> Cheers, Gene
> People having trouble with vz bouncing email to me should add the word
> 'online' between the 'verizon', and the dot which bypasses vz's
> stupid bounce rules.  I do use spamassassin too. :-)
> Yahoo.com and AOL/TW attorneys please note, additions to the above
> message by Gene Heskett are:
> Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
>
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--
Franck