mab@aplcen.apl.jhu.edu (N Brockway mark alle 301-725-8427) (03/26/91)
We currently have a dilemma in operating our machine. We have almost 2GB of disk data that needs to be backed up and it takes way too long :-(. This is the hardware/software configuration: Unisys U6000/80 (Sequent Symmetry S81) Dynix 3.0.12.1 SCSI Bus with 12 1GB SMD Disk Drives 3 Dual Disk Controllers Multibus with 2 1/2 QUAD Tape drives 128 tty ports (connected to the Multibus) Mapper DBMS We use the Mapper software to do our incremental and full backups. This is a software-specific PURGE procedure. To do the full backup takes over ten hours. What we would like to do is purchase either a third-party 8mm cartridge device or a Unisys 4mm DAT device. The third-party 8mm drives I've looked into run off the Multibus using a PERTEC interface. Unisys does not currently market a 8mm device for this machine with this (or any later version) operating system. Their 4mm DAT drive runs off the SCSI bus. I have the following questions: 1) I do not know much of anything about these two options. Can anyone tell me what are the advantages/disadvantages of these two technologies? 2) Unisys Customer Engineers claim that given that their 4mm runs on the SCSI and that the 8mm will run off the Multibus, the 4mm throughput would be better. Can any shed some light on this? [I hate to rely on someone who is looking to make money off my decision.] 3) Could anyone give me an idea of how our backup times would be reduced with these options? 4) What other considerations are there in using these technologies (i.e. compatibility, future viability, etc.)? 5) Do we need to upgrade the operating system to ptx in order for the new peripherals to work? Unisys wants to force us to ptx for their 4mm DATs. Please excuse my ignorance. Any information is greatly appreciated. -- Mark A. Brockway | Internet mab@aplcen.apl.jhu.edu Bell Atlantic | Phone (301)595-2357 11700 Beltsville Dr., Ste 600 | Beltsville, MD 20705 | ** These are my own opinions **
dsm@prism.gatech.EDU (Daniel McGurl) (03/26/91)
In article <1991Mar25.193731.5700@aplcen.apl.jhu.edu> mab@aplcen.apl.jhu.edu (N Brockway mark alle 301-725-8427) writes: >We currently have a dilemma in operating our machine. We have almost 2GB >of disk data that needs to be backed up and it takes way too long :-(. This is >the hardware/software configuration: I'm the system administration for a Unisys 6000/70, and we use a 4mm dat running off SCSI. Using plain old cpio under ptx the backups take 1:30-2 hours to store over 1 gigabyte of data. It's really nifty because it all fits on a single tape. One thing to be careful (in the event that you get one :), is that they system configuration entry for the DAT device is listed as a disk drive, so you have to be careful to add it back in. I removed the entry thinking it was a SCSI disk and the system hung the next time I tried to use the tape drive. -- Danny McGurl "How straightforward the game Office of Information Technology and when all its rules are respected." Information and Computer Science Major at: Georgia Institute of Technology ARPA: dsm@prism.gatech.edu