Sorry, I just noticed now the one data set is encrypted and the other is
not.
Quite a noticeable difference

-----Original Message-----
From: Justin Piszcz [mailto:jpiszcz AT lucidpixels DOT com] 
Sent: 02 March 2010 14:49
To: Shekel Tal
Cc: Kevin C; veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Sun/StorageTek based LTO4 encryption



On Tue, 2 Mar 2010, Shekel Tal wrote:

> I have also been looking at this as an option.
> One of the considerations is the effect encryption has on compression.
>
> I have heard you loose the ability to compress effectively when using
> compression.
>
> Have you noticed an effect on your tape drive compression when using
> tape drive based encryption?
Yes.

LTO-4 TAPE = 800GB

IBM LTO-4 ENCRYPTED (RATIO = ~1.5:1)
ABCD25   3     67   02/17/2010 20:00  02/23/2010 00:00   hcart
1188618163     0
               MPX   03/26/2010 00:00        N/A         FULL ENCRYPTION

ABCD36   3    101   02/18/2010 00:12  03/02/2010 00:00   hcart
1239789810     0
               MPX   04/02/2010 00:00        N/A         FULL ENCRYPTION

IBM LTO-4 NO ENCRYPTION (RATIO = ~3.1:1)
ABCD49   2   1144   02/23/2010 02:43  02/26/2010 01:32   hcart
2451541654     0
               MPX   03/19/2010 02:49        N/A         FULL

ABCD50   2   1350   02/26/2010 01:32  03/01/2010 01:05   hcart
2377975447     0
               MPX   03/22/2010 02:05        N/A         FULL

ABCD51   2   1275   02/24/2010 20:01  02/27/2010 10:40   hcart
2575741349     0
               MPX   03/20/2010 11:40        N/A         FULL

Justin.

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