On Jun 28, 2007, at 12:24 PM, Avy Wong wrote:

Hello Guru(s),

      When it comes to data compression on the client side, is it
true that
when the  data sent to tape drives  it will be compressed again?
are all
tape drives for data compression default set to yes?  How can I
find that
out? ...

Avy -

Compression is governed by your Devclass settings.
You can typically verify that compression is set via OS queries; for
example, in AIX one can do like 'lsattr -El rmt0'.
The compression algorithms in tape drive hardware are usually the
best, and though will attempt compression per your settings, the data
will not expand as in some host software compression algorithms.
Client-side compression is often not used, because it so taxes the
client; but this has to be balanced against network loading, the
other major factor.

   Richard Sims