Amanda-Users

Re: new feature: client-side, server-side encryption dumptype option

2005-12-10 16:26:58
Subject: Re: new feature: client-side, server-side encryption dumptype option
From: Ian Turner <ian AT zmanda DOT com>
To: Gene Heskett <gene.heskett AT verizon DOT net>
Date: Sat, 10 Dec 2005 16:13:29 -0500
Gene,

On Saturday 10 December 2005 02:33 pm, Gene Heskett wrote:
> The patch itself may be great, Kevin, BUT Bzip2 isn't anywhere near as
> dependable as gzip.

That is because bzip2, by default, uses a much larger block size than gzip. 
Gzip's default block size is a mere 32k, whereas bzip2 uses a default 900K 
block. That's one of the reasons bzip2 can deliver such better compression. 
Even so, it's wrong to say that bzip2 silently ignores errors in compressed 
files. If a CRC check fails, you get this message:

bzip2: Data integrity error when decompressing.
        Input file = foo, output file = bar

It is possible that the compressed file(s) have become corrupted.
You can use the -tvv option to test integrity of such files.

You can use the `bzip2recover' program to attempt to recover
data from undamaged sections of corrupted files.

If you find a case where bzip2 silently fails to report an archive error, tell 
us how to reproduce it. Maybe the problem can be fixed.

Cheers,

--Ian