I've received about a dozen responses, and the general consensus seems to
be that, since nobody (who responded) has filesystems as big as 2 Gigabytes,
it doesn't matter what you use for the dump parameters, as long as they
indicate the tape can hold at least 2.3G.
I got varying responses about the blocking factor (20, 56, 64, and 126).
I heard (but have no evidence to support) that the blocking factor doesn't
matter; that the exabyte always uses its own block size, and buffers data
until it gets that much. I also heard that people occasionally have problems
using large block sizes over a network with rdump.
Some people (with whom I agree) insist that you need to lie to dump
about the tape parameters. My impression about why this is needed is that
dump assumes that the tape density won't exceed (my guess) 64K. So you either
use a real big size parameter, or a combination of a large density and a
large size parameter.
The responses are below. Thanks to everyone. Have fun.
Brian
From: lbd@alux4.att.com (Leslie Dreyer)
Blocking factor= 126
Density = 54000
Length (in feet) = 6000
From: phil@dgbt.doc.ca (Phil Blanchfield DGBT/DIP)
rdump 0usf 120000 tapemaster@marvin:/dev/nrmt0h /dev/roota
From: hall@hunter.crim.ca (Ron Robert Hall)
/etc/dump ${level}uncsdf 346 466033 /dev/nrst1 /dev/xd0a #/
From: Loki Jorgenson Rm421 <loki@Physics.McGill.CA>
dump u0bdsf 56 54000 6000 /dev/nrst0 /dev/rpart# >>&! /usr/adm/backup.log
From: matt@wooglin.asd.contel.com (Matthew S. Granger)
dump 0ubsdf 20 6000 54000 /dev/rst1
From: bchivers@smiley.mitre.org (Brent Chivers)
/etc/rdump 0bdsfnu 126 54000 6000 hostname:/dev/nrst0 partition
From: csmoko@relay.nswc.navy.mil (Chuck Smoko - E41)
dump the -s and -d options of 9999999 and 10000. The size params of
From: aptcorp!venus!brian@Central.Sun.COM (Brian Holgate)
dump 0ufs venus:/dev/nrst1 126000 /dev/rxy0a.
From: katz@rpal.com (Morry Katz)
set dumpflags="ubsdf 56 5190 4100000"
From: "r.d. parachoniak" <rap@physics.ubc.ca>
Here are the parameters we use: density=54000 size=6000.
From: jerry%asc@boulder.Colorado.EDU (Jerry Stachowski)
/etc/rdump 0ucbsf 126 160000 discovery:/dev/nrst1 /dev/rsd1g
From: aldrich@sunrise.Stanford.EDU (Jeff Aldrich)
/etc/rdump 0ufbs sunrise:/dev/nrst1 64 125000 /
From: iotek!mike@cs.utexas.edu (Michael A. Thompson, Iotek Inc)
rdump 0ufbsdc tapehost:/dev/nrst0 100 6000 54000 /dev/rsd0a
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:05:58 CDT