I am having a problem on one of my machines and I was wondering if anyone has encountered anything similar.
I have an F740 running 5.3.4R2, with a directly attached AIT-2 tape library. When I first tested the tape drive it performed wonderfully. Once I was happy with the 740 and with the tape drive, I moved the bulk of the data from a pair of old F230's over to the F740. The problem I then encountered is that when I am dumping to the tape it writes 50 gig and then aborts. I am using the "36C" AIT-2 tapes and I am accessing the tape drive using device "nrst0a", so I should be able to write approximately 72 gig of data to the tape. I have tried several different tapes and get the same results. I also tried setting the tape drive into DLT7000 emulation and I still get the same results.
The qeustion now is: is there something wrong with the tape drive or is this a problem with 5.3.4R2? Should I try upgrading to 5.3.4R3? I have another F740 with a DLT7000 library on it and it seems to work just fine. Did I blunder badly by switching to AIT-2?
Ah! Unless your data is very well formed (almost pure ascii) you're getting about what we expect on a drive. Remember that some files are already compressed (zip files, jpg files, some movie formats) you can't meaningfully compress them. In fact as far as we can tell a file system full of .gz files seems to grow when written to a compressing tape.
13.2 GB filesys writes 13.5 GB to the drive and uses 15.1 GB of tape. 13.6 GB filesys writes 13.8 GB to the drive and uses 15.4 GB of tape.
I'd allow 50 Gb per drive, you may actually get a little more that that, but running out of tape is a royal pain.
Please help!!!!!
-- David H. Brierley Raytheon Electronic Systems, Naval & Maritime Integrated Systems Engineering Technology, Operating Systems Support Group
----- Stephen C. Woods; UCLA SEASnet; 2567 Boelter hall; LA CA 90095; (310)-825-8614 Finger for public key scw@cirrus.seas.ucla.edu,Internet mail:scw@SEAS.UCLA.EDU