Is there a way to make rdump to Exabyte faster?

[John Haxby]

In article <1991May7.170515.2915 at morrow.stanford.edu>, caroline at pangea.Stanford.EDU (Caroline Lambert) writes:

|> So my question is: what parameters can I use to make the backup 
|> 		   go faster?

The trouble with the rmt protocol is that it is a stop-and-wait
protocol which effectively prevents the Exabyte from streaming.

I do a remote dump to a DAT drive (4mm instead of 8mm, and
smaller, but otherwise similar) using rsh and dd, viz

	dump Nuf - | rsh tapehost dd bs=10k of=/dev/nrmt0h conv=block

(N is the level of the dump.) It isn't as fast as it could be (the pipe and
rsh are a bit of a bottleneck), but at least the tape streams.  I get
around 140kbytes/second from a big VAX to a DECstation 5000--different
hardware, of course, will give different behaviour.

For my purposes, rsh is fast enough as I can more-or-less fill a 1Gb
tape in a couple of hours.

-- 
John Haxby, Definitively Wrong.
Digital				<jch at wessex.rdg.dec.com>
Reading, England		<...!ukc!wessex!jch>

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The opinions expressed herein are my own, not my employers.