Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!apple!ames!amdahl!pacbell!att!chinet!les
From: les@chinet.chi.il.us (Leslie Mikesell)
Newsgroups: comp.sys.att
Subject: Re: 9track on 3b2
Message-ID: <8791@chinet.chi.il.us>
Date: 28 Jun 89 14:31:04 GMT
References: <125@bdofed.UUCP>
Reply-To: les@chinet.chi.il.us (Leslie Mikesell)
Organization: Chinet - Public Access Unix
Lines: 22

In article <125@bdofed.UUCP> nickerso@bdofed.UUCP (b) writes:
>Hello World!
>	Hi.  We're having trouble with backups on a 9track.  We have two
>3b2s (a 622 and a 700).  We have the tape unit on the 700 and ethernet
>between the two.  We have /dev mounted under RFS on the 622.  The problem
>is that the backups are taking FOREVER! (well, almost :-)  The backup of
>the 700 machine uses 1 1/2 2400 foot tapes (at 6250) and takes over 2
>hours! 

I've tried this with 3b2/400's with 1M starlan and cartridge tapes
and found that it works better to mount the remote disk into the
machine with the tape drive instead of accessing the tape device
remotely.  This does require root access to the remote files
(map 0:0) but that is not a problem here.  An alternate possibility
without special programming would be to create a FIFO in a common
directory to pass the data (Has anyone tried this?).
For a more dramatic improvement you need a method of double-buffering
on the machine that has the tape drive so the network and tape
io can overlap. Also a program that would make a TLI level link directly
between the machines would help by eliminating the RFS overhead.

Les Mikesell