[comp.unix.ultrix] rdump from VAX to DS5400

barrett@jhunix.HCF.JHU.EDU (Dan Barrett) (07/16/90)

In article <5814@jhunix.HCF.JHU.EDU> I wrote:
>	I attempted to use rdump to backup our VAX 8530 (Ultrix 2.0)
>onto the tape drive (TU81+) on our DECsystem 5400 (Ultrix 3.1d).
>
>		DUMP: Protocol to remote tape server botched (code @?).
>		Lost connection to remote host.

	A few more points to follow-up my original posting:

o	Yes, I know about the "o" compatibility switch for rdump and
	rrestore.  It doesn't work when dumping from a 2.0 machine to
	a 3.1 machine, as far as I can tell.  (I assume it works the
	other way around.)  2.0 has no "o" switch at all.

o	I did manage to back up our VAX by doing:

		On VAX:		rdump 0uf server:/tmp/root.dump /

		On DS5400:	dd if=/tmp/root.dump of=/dev/rmt1h bs=10k

	Not ideal, but it works.  (But I cannot rrestore from the tape
	drive anyway... gotta go back to disk first, then rrestore from
	the file.)  :-(  

Still flailing...

                                                        Dan

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D. Allen [CGL]) (07/16/90)

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