On Saturday 21 September 2002 16:05, Neil wrote:
>Gene Heskett writes:
>>>> 5) rerun the tapetype and get the true capacity of the tape so
>>>> you can update that entry in your amanda.conf.  It should go
>>>> up a bit because tapetype uses /dev/urandom as the data source
>>>> for its test writes, and the data from /dev/urandom is so
>>>> random that it overpowers the hardware compression and
>>>> actually grows to be larger on the tape than what tapetype
>>>> seems to think it is.
>
>Here is the newly generated conf generated by tapetype program:
>define tapetype unknown-tapetype {
>   comment "just produced by tapetype program"
>   length 3916 mbytes
>   filemark 174 kbytes
>   speed 446 kps
>}
That looks a bit more like it.
>
>Previously, it was:
>define tapetype C1533A_120 {
>   comment "HP C1533A DDS2 with 120m tapes"
>   length 3858 mbytes
>   filemark 107 kbytes
>   speed 507 kbytes
>}
>
>On the box of my tape, it says there 8 gig compressed. How will I
> be able to achieve this? Are my new values fine or should the
> digit appear as near 8 gigs in value?

No, this 3916 mbytes is the real capacity of *that* tape.  Amanda 
counts byte going to the tape *after* any software compression has 
been done.

The box contains whatever the marketing weenies want to claim, and 
they always claim a value thats about the mean (rounded up to the 
next gig mind you) of twice the actual based on everybody using the 
hardware compression.

Software beats that most any day of the week by wide margins.  I 
have a report from not too long ago that advises me it used 3940 
mbytes of the tape (its rare a backup is that big here), but that 
the source before any compression was applied was nearly 12 
gigabytes!  This on the same tape you're using in a Compaq (Seagate 
4586np) changer, without hitting EOT.  But I'd bet the unused was 
measured in inches & not very many of them at that.

>I don't know if this link will help. This is the exact tape that I
> have right now. http://www.cmm.bg/h-p/doc/70/c5707a.htm
>
>Thanks again.
>
>Neil

-- 
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz  512M
99.15% setiathome rank, not too shabby for a WV hillbilly