Backup Exec 12 compression and encryption

[ardi26]

I'm using software encryption to encrypt data in tape and software compression.
The compression ratio shows 1:1 when encryption is used, while without encryption the ratio is 1.5:1
I'm using HP LTO 64KB tape drive. The compression option is checked under device properties for the tape drive.
Has anyone faced this problem before?
Why the compression is not taking place even software encryption and software compression is used.
I'm using Symantec backup exec v 12 with the latest service pack and patches.

Thanks.

[Abhijit_Soman]

Hi,

Always keep in mind when software encryption is enabled, data will never get compressed.

This rule is not only applicable to Backup Exec but applicable to all softwares.

If you will backup with hardware encryption, data may get compress because hardware compression is enabled on drive but for this you will required hardware compression compatible drives.

[ardi26]

Hi, how can I tell if the tape device supports Hardware encryption?

Thanks

[Larry_Fine · Accepted solution]

The HCL shows which tape drives are supported with hardware encryption.
http://www.symantec.com/business/support/documentation.jsp?language=english&view=comp&pid=15047
Looking at the drive properties in BE will also show the capabilites of the drive.

HP LTO4 drives have encryption.  Previous generations do not.

[Paul_Ryan]

Hi,

Following up onthis, as I was having problems getting Hardware compression to work - turned off the software encryption, and the hardware compression now appears to be working. Still testing.

Regards

[teiva-boy]

 Correct, you need to pick one or the other, not both.  

In one way, software compression is better...  On newer hardware that is.  The data is compressed BEFORE sending it over the wire, that means less network traffic.  Which is a good thing.
However the cost is extra CPU cycles on the host.

If you turn on encryption in BE, no one can sniff your traffic along the way.  Again, the cost is CPU cycles.


You can do it all in hardware within LTO4 drives, and older tape tech can do compression in hardware.  With little additional overhead.  

That said, I prefer for my newer hardware in the last few years, to use compression on the host, and encryption on the drive or within the media server if applicable.