Newsgroups: comp.unix.ultrix
Path: utzoo!utgpu!watserv1!watcgl!idallen
From: idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL])
Subject: Re: rdump from VAX to DS5400 (use dd, not rdump!)
Message-ID: <1990Jul16.151116.1804@watcgl.waterloo.edu>
Summary: use dd, not dump or rdump, on Ultrix
Organization: Computer Graphics Laboratory, University of Waterloo, Ontario, Canada
References: <5814@jhunix.HCF.JHU.EDU> <5815@jhunix.HCF.JHU.EDU>
Date: Mon, 16 Jul 90 15:11:16 GMT
Lines: 75

Some timings you might be interested in.

Ultrix dump of root to nowhere:

    bandicoot# time dump 0f - / >/dev/null
    [dump stuff deleted]
    16% real=0:22 usr=0.9 sys=2.7 rd=8 wr=4 mem=332 pg=0 rec=0 sw=0
	sig=0 cs=959

BSD dump of root to nowhere:

    bandicoot# /software/dumpster/maintenance/dump 0f - / >/dev/null
    [dump stuff deleted]
    6% real=0:31 usr=1.0 sys=1.2 rd=10 wr=14 mem=252 pg=10 rec=46 sw=0
	sig=0 cs=582


Ultrix rdump of root to nowhere:

    bandicoot# time /bin/rdump -0f bandicoot:/dev/null /
    [dump stuff deleted]
    39% real=0:55 usr=2.8 sys=19.1 rd=2 wr=6 mem=282 pg=3 rec=60 sw=0
	sig=0 cs=4533

BSD rdump of root to nowhere:

    bandicoot# time /software/dumpster/maintenance/rdump
	-0f bandicoot:/dev/null /
    [dump stuff deleted]
    33% real=0:39 usr=1.9 sys=11.2 rd=10 wr=17 mem=283 pg=12 rec=64 sw=0
	sig=0 cs=5002

Ultrix rdump of root to a real tape:

    bandicoot# time rdump -0f recorder:/dev/nrmt0h /
    [dump stuff deleted]
    [I hit break after 6 minutes when dump estimated the dump
     would take another 20 minutes]

BSD rdump of root to a real tape:

    bandicoot# time /software/dumpster/maintenance/rdump
	-0f recorder:/dev/nrmt0h /
    [dump stuff deleted]
    [I hit break after 7 minutes when dump estimated the dump
     would take another 13 minutes]

Ultrix dump of root to rsh/dd to a tape:

    bandicoot# time dump 0f - / | rsh rec dd bs=32k rbuf=2 wbuf=2 of=/dev/rmt0h
    [dump stuff deleted]
    7% real=1:31 usr=1.0 sys=6.0 rd=2 wr=4 mem=351 pg=0 rec=3 sw=0
	sig=0 cs=4900
    15% real=2:48 usr=2.5 sys=24.1 rd=15 wr=7 mem=206 pg=0 rec=3
	sw=0 sig=0 cs=10300

BSD dump of root to rsh/dd to a tape:

    bandicoot# time /software/dumpster/maintenance/dump 0f - / 
	| rsh rec dd bs=32k rbuf=2 wbuf=2 of=/dev/rmt0h
    [dump stuff deleted]
    2% real=1:31 usr=1.0 sys=1.1 rd=5 wr=16 mem=216 pg=2 rec=54 sw=0
	sig=0 cs=534
    13% real=2:53 usr=2.7 sys=20.7 rd=11 wr=16 mem=159 pg=2 rec=54
	sw=0 sig=0 cs=6983

What I learned:

    Don't use rdump.  It's an order of magnitude slower than a pipe to dd.
    In fact, even dump is slower than dump to stdout piped into dd with
    wbuf=2, because of bugs in the Ultrix nbuf code.  At least Ultrix dd
    handles multiple tapes and multi-buffer writes; isn't that convenient?
-- 
-IAN! (Ian! D. Allen) idallen@watcgl.uwaterloo.ca idallen@watcgl.waterloo.edu
 [129.97.128.64]  Computer Graphics Lab/University of Waterloo/Ontario/Canada