From:	SMTP%"MACRO32%WKUVX1.BITNET@uu7.psi.com" 25-AUG-1993 10:18:07.14
To:	EVERHART
CC:	
Subj:	RE: A puzzle on single disk systems

X-Listname: "VMS Internals, MACRO, & BLISS Discussions" <MACRO32@WKUVX1.BITNET>
Warnings-To: <>
Errors-To: MacroMan%WKUVX1.BITNET@uu7.psi.com
Sender: MacroMan%WKUVX1.BITNET@uu7.psi.com
Message-Id: <0097146F.6CFCF026.18596@WKUVX1.BITNET>
Date: Thu, 19 Aug 1993 23:49:21 -0400
From: "(Jon Pinkley, Westinghouse (216)486-8300 x1335)"
      <tron!clevax.dnet!jon@uunet.uu.net>
Reply-To: MACRO32%WKUVX1.BITNET@uu7.psi.com
To: "uunet!WKUVX1.BITNET!MacroMan"@uunet.uu.net
Cc: JON@uunet.uu.net
Subject: RE: A puzzle on single disk systems

I'm sure you will get lots of responses on this.  I think it's been discussed
at VAX Magic sessions.

1. Create a "virtual" disk of some kind.  Use either Gerard Newman's
   RAMdisk or a container file based one using Glenn Everhart's VDDRIVER.
   It can be a relatively small virtual disk (I don't know how small off
   hand but 1000 blocks should be sufficient for reasonable cluster
   sizes).

2. Initialize the virtual disk using the cluster size you want, and with
   the other parameters the way you want them.  You will probably want to
   specify /maximum_files so VMS doesn't use its algorithm, since it uses
   the disk size as an input.

3. BACKUP/IMAGE the empty virtual disk to tape.

4. Boot stand alone backup.

5. BACKUP/IMAGE the disk you want to change cluster size of to tape
   (Don't forget this!!!!)

6. BACKUP/IMAGE/INIT tape: disk:  ! using backup of empty virtual disk

7. BACKUP/IMAGE/NOINIT tape: disk:  ! using backup of the original disk

You should now have a disk with the original contents but a different
cluster factor.

Or you could patch backup to put the desired clustersize into the backup
image saveset header :-)

Jon Pinkley  jon@clevax.wec.com