Subject: ccd and cylinder locations
To: None <>
From: gabriel rosenkoetter <>
List: current-users
Date: 01/18/2002 11:01:44
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My /mp3 recently ran out of space, meaning it's time for me to go
buy another ridiculously huge IDE drive and learn how to use ccd.

To start off, I'm reading ccd(4) and found this tidbit:

     Note that the `raw' partitions of the disks must not be combined.  Each
     component partition should be offset at least one cylinder from the be-
     ginning of the component disk.  This avoids potential conflicts between
     the component disk's disklabel and the ccd's disklabel.


My disklabel:

4 partitions:
#        size    offset     fstype  [fsize bsize cpg/sgs]
 a:  80023104         0     4.2BSD   1024  8192    16   # (Cyl.    0 - 7938=
 d:  80023104         0     unused      0     0         # (Cyl.    0 - 7938=

Is there a clean way that doesn't involve another disk to nudge the
blocks on that disk back a sector and clear off the first one
(redisklabling the disk, of course)? (It'd be easy to make enough
space at the end of the drive, provided we've got something to move
the blocks around.) Yes, I'm well aware that I could write something
to do this to the raw device myself, since the concept is quite
simple, but I figured I couldn't be the first to want to do this and
man -k has yet to be helpful.

Does the fact that I do not now, nor will I ever want to, boot from
this drive save me any? (That is, do we reserve space at the
beginning of a: for boot blocks that I could safely shove aside,
or is that before the beginning of a:, and so already not there on
this disk?)

Or am I screwed on trying to retain the file system on the disk
right now anyway? (Neither ccd(4) nor ccdconfig(8) makes it clear
whether it's necessary to newfs the partitions of a disk before
making it part of a ccd.)

gabriel rosenkoetter

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