[Bacula-users] Encryption and compression

2007-10-30 Thread Eric Böse-Wolf
I did a few test and maybe someone is interested in the results.

I did a backup of the linux kernel documentation, quite a lot of
text ("du -sh ." gives 22M in the directory), under different
conditions, each of those backups I wrote to a new file volume and
here are the sizes of the file volumes:

Keylength   Compression(GZIP)  Resulting Mediasize (Bytes)
noneno 17299177
noneyes 6638157
1024no 18840845
2048no 19751779
4096no 21519151
1024yes 8179802
2048yes 9091106
4096yes10858478

If you compress and you have a damaged tape, you will lose more date as
if you did not use compression, but for encryption the tape is wothless
with only a single failure to, so I think if you use encryption you can
also use compression, if you have the CPU power for it. (The time a
backup needed increased significantly with the keylength, but I did not
measure exact times here.)

Yours sincerely,

Eric Böse-Wolf

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Re: [Bacula-users] Encryption and compression

2007-10-30 Thread Rich
On 2007.10.30. 13:21, Eric Böse-Wolf wrote:
> I did a few test and maybe someone is interested in the results.
> 
> I did a backup of the linux kernel documentation, quite a lot of
> text ("du -sh ." gives 22M in the directory), under different
> conditions, each of those backups I wrote to a new file volume and
> here are the sizes of the file volumes:
> 
> Keylength   Compression(GZIP)  Resulting Mediasize (Bytes)
> noneno 17299177
> noneyes 6638157
> 1024no 18840845
> 2048no 19751779
> 4096no 21519151
> 1024yes 8179802
> 2048yes 9091106
> 4096yes10858478
> 
> If you compress and you have a damaged tape, you will lose more date as
> if you did not use compression, but for encryption the tape is wothless
> with only a single failure to, so I think if you use encryption you can
> also use compression, if you have the CPU power for it. (The time a
> backup needed increased significantly with the keylength, but I did not
> measure exact times here.)

maybe this should be added to the wiki ?

> Yours sincerely,
> 
> Eric Böse-Wolf
-- 
  Rich

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