Michael D. Schleif wrote:
[1] Should I use hardware compression?
There seem to be several schools of thought here. I want to know how
Amanda works with hardware compression? What are the advantages of
using software compression? What are the disadvantages of using *both*
hardware and software compression?
See Kurt's answer. May I add that using both hardware compression
and software compression at the same time actually lowers the
capacity of your tapedrive (a DAT-tape, you said).
If you blindly impose the compression algorithm on an already
compressed data will enlarge that data. Now much depends on the
algorithm. DAT-tapes use something from the "compress" family.
Try:
compress somefile
cat somefile.Z | compress -v | wc -c
Gzip does much better, by implementing a way to indicate
that next few bytes are not compressed.
cat somefile.Z | gzip -v | wc -c
The only drive I know without that problem is an LTO1 drive.
see:
http://groups.yahoo.com/group/amanda-users/message/44455
[2] What are the optimal dumptypes for my situation?
I would go for gnutar, compress client fast, index, record, and
apropriate priority (user-data = higher, system = lower).
--
Paul Bijnens, Xplanation Tel +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512
http://www.xplanation.com/ email: [EMAIL PROTECTED]
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