Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!samsung!olivea!uunet!mcsun!cernvax!chx400!bernina!karrer From: karrer@bernina.ethz.ch (Andreas Karrer) Newsgroups: comp.unix.ultrix Subject: Re: Is there a way to make rdump to Exabyte faster? Message-ID: <1991May8.104300.1730@bernina.ethz.ch> Date: 8 May 91 10:43:00 GMT References: <1991May7.170515.2915@morrow.stanford.edu> Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH Lines: 28 caroline@pangea.Stanford.EDU (Caroline Lambert) writes: [...] >Doing a remote dump from a DEC5000 (Ultrix 4.1) I am using the >parameters recommended by the manufacturer of the tape drive, >for lack of anything better (there's no 'b' parameter for the ultrix rdump). >This is for a 2GB tape: >rdump 0unsdBf 346 4137733 2097152 tapemachine:/dev/nrmt0h /filesystem we don't use rdump anymore. we use basically dump 0uf - /dev/r | rsh tapehost "buffer -s 126b > /dev/" and get transfer rates (DECsystem 5500 -> Sun 4/490) of 220KB/s, close to the streaming speed of the exabyte (246 KB/s ?). buffer is a highly useful program written by Lee McLoughlin, Imperial College (lmjm@doc.ic.ac.uk or lmjm%uk.ac.ic.doc@nsfnet-relay.ac.uk). It is basically a "dd" that splits itself into two processes that communicate thru shared memory and does re-blocking. we run it under SunOS 4.1.1 and Ultrix 4.[0|1]. buffer was posted to alt.sources some time back, but i can't readily find it on any ftp site. so i put it on ural.ethz.ch[129.132.1.45]:software/source/buffer.tar.Z +----------- Andi Karrer, Communication Systems, ETH Zuerich, Switzerland karrer@bernina.ethz.ch - terible simplifieur /s=karrer/ou=bernina/o=ethz/prmd=switch/admd=arcom/c=ch/