[nylug-talk] Recommendations for encrypted tape drive(s)?

[Luis Murillo]

Ok, I agree some of the data you provide is not something I can go up
against at...but one thing I can say that you missed is the LTO4
speed...the LTO4 can reach speeds of up to 240MBps on an ideal system
but since that's not always correct, I've seen the drives work around
160MBps and would consider a drive that is doing less that 150MBps to
be having performance issues...at least on SCSI :)

The scenario I wrote about it's completely true...I've seen it happen
on the drives that I support.

-LM

On 3/4/08, Alex Pilosov <alex at pilosoft.com> wrote:
> On Tue, 4 Mar 2008, Luis Murillo wrote:
>
>  > Software compression and encryption means that the backup job will
>  > take longer, specially when data is being transfered to the tape
>
> BS, CPUs can encrypt far faster than tape drive can move. upgrading cpu is
>  far cheaper than adding encryption to the drive.
>
>  On P4/3.0 (already *old* hardware) you could do 200Mbyte/sec of AES. On
>  each core of something more modern like 5440, you could do 400Mbyte (times
>  4 cores). LTO-4 (fastest drive) is 120MB/s. LTO-4 has hardware AES
>  specified in the drive, but personally, I'd avoid.
>
>
>  > drive, and delaying the stream of data is something that you don't
>  > want to happen since it will create more wear and tare with the media.
>  > If data is not streamed to the drive fast enough then it will cause
>  > for the drive to stop rewind and start writing again...all throughout
>  > the process the head will be touching the media in order to go back to
>  > the point where the last bit of data was written and this is what
>  > causes for the media to be worn out faster.
>
> Yeah, I doubt it'd happen.
>
>
>  > So the hardware encryption and compression are done on the tape drive
>  > itself which means that the system can simply dedicate it's resources to
>  > streaming the data to the tape drive and not have to use processing
>  > power to do that. Also most of the people don't have a dedicated server
>  > and with the newest tape drives you need the most out of your system in
>  > order to have the drive perform the fastest. In some older tape drives
>  > you actually would loose capacity of the media because of that constant
>  > stopping, because the drive instead of stopping and rewinding would
>  > start writing zeros to the media which meant that the media had blocks
>  > of zeros just taking up space.
>
> I doubt anyone has tape drive that can write than cpu can encrypt.
>
>
>  -alex
>
>
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-- 
LuisM