On Fri, Nov 16, 2007 at 08:43:35AM -0800, X_S wrote:
> ok, thanks for your response.  reason is, we're testing a new
> encryption product (compresses/encrypts) and the lto3 is new to me as
> well.  I did see elsewhere that the lto3 will disable compression
> automatically if it has to but i don't know how to confirm that this
> is actually happening.  therefore, i just wanted to see if i can
> disable it from the get-go so i can be sure that the results that i'm
> looking at are real.

Sounds good.  If you have a scratch tape and the time to do it, I'd run
a 'dd' test.

mt -f /dev/rmt/0cbn rewind
dd if=/dev/zero of=/dev/rmt/0cbn bs=256k
mt -f /dev/rmt/0cbn rewind
dd if=/dev/zero of=/dev/rmt/0hbn bs=256k

Count the number of blocks transferred and multiply by 256K to get
bytes.  The first should be several times larger than the second due to
the high compressibility of the zeros.

-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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