Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!purdue!decwrl!shelby!portia!forel!karish
From: karish@forel.stanford.edu (Chuck Karish)
Newsgroups: comp.sys.ibm.pc.rt
Subject: Re: Backup info for RT Wanted
Message-ID: <4160@portia.Stanford.EDU>
Date: 2 Aug 89 02:57:47 GMT
References: <12237@well.UUCP>
Sender: USENET News System <news@Portia.stanford.edu>
Reply-To: karish@forel.stanford.edu (Chuck Karish)
Organization: Mindcraft, Inc.
Lines: 36

In article <12237@well.UUCP> gors@well.UUCP (Karin Meyer) wrote:

>Hello, I am trying to figure out how to do regular backups on 
>an IBM RT running AIX 2.2.1.  I would like to use "backup" format
>since it appears to be much faster than tar, as well as having an
>incremental backup system built into the command.

	Tar isn't too bad if you use the `-C' flag to send many blocks
	at once.  I always use `-C800' as a separate command-line
	parameter to tar.  This writes 400K to the tape at once, and
	the drive doesn't saw back and forth interminably writing 10K
	at a time (the default).

	Related question:  Have I missed something, or does AIX lack a
	generic utility to buffer input to the tape drive so it'll
	stream?  I'd like to do remote backups, but dd doesn't have the
	`-C' option.  It seems wasteful to me to support the same code
	in all tape utilities to do this.

>I can't seem
>to give the backup command more than one volume to back up at once.

	Backup is oriented towards backing up individual disk
	partitions, one per file.  It does that job well.  You can use
	a shell script to manage multiple partitions.

>Nor does it appear to have a flag which allows incremental storage
>on my tape.  Is there any way of backing up several volumes to the
>same tape?

	As with most UNIX tape utilities, you can back up several files
	to the same tape by choosing a no-rewind tape device (/dev/rmt4
	or /dev/rmt12).

	Chuck Karish		{decwrl,hpda}!mindcrf!karish
	(415) 493-9000		karish@forel.stanford.edu