SUMMARY: Exabyte 8505XL with 14 gb compression under Solaris 2.5.1

From: Jason Keltz (jas@cs.yorku.ca)
Date: Fri Nov 07 1997 - 06:54:27 CST


To summarize my original message, I had two problems:

1) Solaris claims to support the 8505XL without changes to st.conf, but
   an mt status on the drive reports "Exabyte EXB-8500". I had wondered
   whether other people saw this, and whether it was the cause of
   problem 2).
2) I couldn't get anywhere near 14 gb out of the drive. I maxed out at
   8 gb.

The response to 1) is that other people with Exabyte 8505 XL's and
Solaris 2.5.1 see the same message, and get the proper compression, so
this isn't the problem. On a side note though -- come on, Sun -- if a device
is supported by the OS, the OS should properly report the device type. This
is a unit in a SUN enclosure, so for paying a higher premium, I expect that
integration.

The response to 2) was interesting. In my message, I said that I used the
"0n" device and should have received the highest compression of the drive.
I filled a tape using 0n, and got only 6.7 gb. What I failed to say is
that I had tried the 0cn device as well (yep, I did read that st man
page). Using 0cn, I got a "whopping" 8gb. Many people said to use 0cn,
and quoted the man page from st. I was also told to try 0hn (which is
supposed to be the same as 0cn for the 8505 XL), 0hbn (similar, but using
BSD compatibility), and most interestly, ufsdump arguments of b (126), d
(54000), and s (37000) along with the 0cn device and Sony 160m tapes. In
the end, I tried a 0cn backup again since at least 2 people told me that
they use this device and get at least 10gb under 2.5.1. I only got 8.8gb.
I tried the ufsdump arguments since that came from a SUN InfoDoc, but
unfortunately, that didn't help either. I guess this is the best I'm
going to do with this device.

Thanks to the following people for taking the time to respond:

Linda S. Gee <u2is9lsg@lindasun.crrel.usace.army.mil>
Thomas A. Plesha <tplesha@nslcpacific.navy.mil>
Mark Hargrave <hargrme@wisdom.maf.nasa.gov>
Andy Paton <Andy.Paton@worktech.co.uk>
James Noad <jehn@cortex.shef.ac.uk>
Thomas Frank <thomas.frank@magnet.at>
Louis Avrami <L.Avrami@dialogic.com>
Brion Leary <brion@dia.state.ma.us>
Douglas Purdy <doug@tor.digidyne.ca>
Glenn Satchell <Glenn.Satchell@uniq.com.au>
Scott F. Woods <sfw@adc.idt.com>
Stuart Spinner <spinner@ce.udel.edu>

Jason Keltz
jas@cs.yorku.ca



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