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From: mohamed@hscfvax.UUCP (750025@Mohamed_el_Lozy)
Newsgroups: comp.unix.questions
Subject: Re: TK-50 tape backups -- could they go faster?
Message-ID: <430@hscfvax.UUCP>
Date: Mon, 22-Jun-87 12:01:37 EDT
Article-I.D.: hscfvax.430
Posted: Mon Jun 22 12:01:37 1987
Date-Received: Tue, 23-Jun-87 04:29:19 EDT
References: <241@kosman.UUCP> <799@mcgill-vision.UUCP> <237@itcatl.UUCP>
Organization: Health Sciences Computing Facility, Harvard University
Lines: 20

In article <237@itcatl.UUCP>, robin@itcatl.UUCP (Robin Cutshaw) writes:
> In article <241@kosman.UUCP>, kevin@kosman.UUCP (Kevin O'Gorman) writes:
> > Running dump(8) on a MicroVAX, Ultrix 1.2A -- and I'm getting REAL
> > tired of waiting for the tape.
> 
> Use b and s flags (bs 126 7400) and it will stream.  Restore will also
> work under Ultrix using the b flag (b 126) flag.  Our backup script follows...

Under our 1.2 Ultrix system, restore(8) does not rcognize the 'b' key.
Since we have all source licenses, we compiled the 4.3 dump/restore
pair and did some timings.  On a single user MicroVAX we got about a
threefold speedup, MOST impressive.  On an 8200 with TU-81 tape drive
we got the following timings on /dev/rra0g, which has about 30 Meg on
it, dumping at 6250 bpi:

	standard dump (no 'b' key)		15:53 clock time
	Ultrix 1.2 dump, b 256			12:10 clock time
	BSD 4.3 dump, b 256			 8:10 clock time

These speedups are most welcome when dumping several ra81's.