Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!cernvax!chx400!pan!jw
From: jw@pan.UUCP (Jamie Watson)
Newsgroups: comp.unix.aix
Subject: Re: PS/2 AIX Tape Utilities & IBM external tape
Message-ID: <977@pan.UUCP>
Date: 7 May 90 21:08:42 GMT
References: <5272@hydra.Helsinki.FI> <1990May5.043843.1659@acheron.uucp>
Reply-To: jw@pan.UUCP (Jamie Watson)
Organization: Adasoft AG, Solothurn, Switzerland
Lines: 20

>If you're going to back up AIX filesystems, you might do better with
>the AIX backup or tar commands.
>Perhaps some AIX guru would be kind enough to give an exact sequence of
>commands for this?

You are correct, using 'dd' and a large block size makes writing tapes
under AIX reasonably fast.  A typical command is:

    $ tar cf - files | dd obs=512k of=/dev/rmt0

The block size can be a large (or small) as your system memory allows;
actually there is only marginal gain above something like 256k.

I would absolutely not recommend using the AIX backup commands if there
is any chance that you will ever need to read the backup tapes on any
non-AIX system.  This is yet another example of IBM inventing a "better"
solution for something that already has several perfeclty adequate
alternatives generally available.

jw