SUMMARY: Dump Parameters

From: Nicholas Franco (
Date: Thu Nov 19 1992 - 17:28:21 CST


My original question:

> Does anyone know a good set of parameters to use when dumping a filesystem
> to another disk drive. I am specifically looking for what parameter one
> would change so that the dump command will not ask you to mount the next
> volume, though any suggestions on how to optimize this type of dump would
> be appreciated. I am dumping from a SS2 ( SUNOS 4.1.1 ) to a 4/490 (SUNOS
> 4.1.1). Thanks.

The majority of the responses were in favor of giving some very large number
for the (s)ize parameter ( 999999 ). Others suggested the same for the
tapelength and density parameters. Others also pointed out that when dump is
redirected to standard out then it will not ask to have the tape changed.

Jay Lessert ( bit!jayl@Sun.COM ) had the most complete answer and so I will
defer to Jay and let you read his email below.

> If you simply simply want to do a fast backup, using the other disk simply
> as fast magnetic media, you just want to use the stdout option of dump (dump
> into a pipe, in other words). Dump then assumes it has an infinite storage
> medium (the pipe) and won't ask for a change. If the dump file will ever wind
> up on tape, use whatever block size you would want on the tape, else block
> size really doesn't matter:
> dump 0ubf 126 - /host1/u0 | rsh host2 dd of=/host2/u0/dumpfile0.host1 obs=63k
> Of course, you could forgo the rsh and just write the dumpfile over NFS, but
> on a generic Sun NFS server this would be much slower (synchronous writes).
> If on the other hand you really want to clone or shadow the file system, then:
> dump 0ubf 126 - /host1/u0 | rsh host2 'cd /host2; restore xbf 126 -'
> Jay Lessert {decwrl,,sun,verdix}!bit!jayl
> Bipolar Integrated Technology, Inc.
> 503-629-5490 (fax)503-690-1498

Thanks to all that responded. trc@NSD.3Com.COM cfoley@arsenic ups!upstage!glenn@fourx.Aus.Sun.COM era@niwot.scd.ucar.EDU bit!jayl@Sun.COM

Nicholas C. Franco			email:
System Administrator			phone: 612-683-3830
Software Information Services		fax  : 612-683-3899
Cray Research, Inc.
655A Lone Oak Drive
Eagan, MN 55121

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