Newsgroups: comp.unix.ultrix Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!sdd.hp.com!elroy.jpl.nasa.gov!decwrl!pa.dec.com!hollie.rdg.dec.com!jch From: jch@hollie.rdg.dec.com (John Haxby) Subject: Re: Is there a way to make rdump to Exabyte faster? Message-ID: <1991May8.085831.24344@hollie.rdg.dec.com> Sender: news@hollie.rdg.dec.com (Mr News) Reply-To: jch@hollie.rdg.dec.com (John Haxby) Organization: Digital Equipment Corporation References: <1991May7.170515.2915@morrow.stanford.edu> Date: Wed, 8 May 1991 08:58:31 GMT In article <1991May7.170515.2915@morrow.stanford.edu>, caroline@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 Reading, England <...!ukc!wessex!jch> ---------------------------------------------------------------- The opinions expressed herein are my own, not my employers.