*BSD News Article 22891


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Newsgroups: comp.os.386bsd.questions
Path: sserve!newshost.anu.edu.au!munnari.oz.au!constellation!convex!convex!cs.utexas.edu!math.ohio-state.edu!howland.reston.ans.net!spool.mu.edu!torn!mcshub!flex1!todd
From: todd@flex.eng.mcmaster.ca (Todd Pfaff)
Subject: backup of DOS partition
Message-ID: <1993Oct27.035034.11525@mcshub.dcss.mcmaster.ca>
Sender: usenet@mcshub.dcss.mcmaster.ca
Nntp-Posting-Host: flex1.eng.mcmaster.ca
Reply-To: todd@flex.eng.mcmaster.ca
Organization: McMaster University
Date: Wed, 27 Oct 1993 03:50:34 GMT
Lines: 25

I use the following in 386bsd to backup a DOS partition to an Exabyte tape drive
on a Sun server over Ethernet.

dd if=/dev/wd0d count=204848 | rsh tapehost dd of=/dev/nrst9

/dev/wd0d is the entire disk and the DOS parition occupies the first 204848 sectors.

This is quite slow; it takes about 45 minutes to complete.  Can anybody suggest a
faster method?

What is likely the bottleneck (disk reads, network, tape writes)?  The server and
network are not under any load at the time.

Could I optimize the use of the network by specifying an output block size for the
first dd command?

Is there a better way to do this than with dd and rsh?

---
Todd Pfaff                       \  Internet: todd@flex.eng.mcmaster.ca
Dept. of Mechanical Engineering   \    Voice: (905) 525-9140 x22902
McMaster University                \     FAX: (905) 572-7944
Hamilton, Ontario, CANADA  L8S 4L7  \