add a harddrive to an existing system

[Matthew Seaman]

Chris wrote:

> I read that also however, I have a question about it. In the example I 
> read (by Doug White) he used /usr/home as the point of reference. The 
> question I have is this, what becomes of the space left over on the 1st 
> drive now that /usr/home has been effectively moved?
> 
> Can you merge this in someplace else? Say /swap or /var?

If you mount the new partition from your new disk at /usr/home, then 
anything under /usr/home *on the old disk* will become inaccessible, and 
just take up space to no purpose.  But you knew that anyhow.

So, after you've copied your original /usr/home data onto the new 
partition, you should delete those contents from the old partition -- 
and that will have exactly the effect you'ld expect on the available 
space in the old partition.

You can't arbitrarily shave bits off one partition and add them to 
another one -- at least, not without going through a great deal of 
rigmarole: backing everything up, booting from separate media if 
necessary, deleting all of the affected partitions, recreating them in 
the required size and restoring the backups.  Note that 'affected 
partitions' will include those located on disk between the partition 
you're expanding and the one you're contracting: in order to shift them 
over a few cylinders, you will have to delete them, go through all of 
the gubbins to recreate each of them in their new positions and then 
restore the contents from backup.  You probably don't want to have to do 
all that.

However, you can add a swapfile on the emptied partition: see 
mdconfig(8) for details (vnconfig(8) if you're using 4.x).

Otherwise you can effectively map chunks of /usr/home into /var by 
adroit use of sym-links.  However this is not particularly recommended: 
it goes against the reason for actually having a separate /var partition 
in the first place, and symbolic link-trees are too prone to silly 
things like not getting backed up properly, or inadvertently causing you 
to try and write to a non-mounted partition.

The installer does rather tempt you into making a large number of 
partitions all over the place, but that temptation should be resisted 
unless you have good solid reasons for splitting up your disks.  In 
general, the rule of thumb is a small number of large partitions will 
serve you better than a large number of small partitions.  Partitioning 
schemes and disk layout are the sort things that sysadmins love to argue 
infinitesimally all the whys and wherefores of -- but note that for a 
home system just having *two* partitions on a drive (ie. swap + 
everything else) will work very well indeed, and save you from having to 
worry about partition juggling at all.  Although that layout is 
certainly not the right solution in all circumstances.  See the archives 
of this list for many, many arguments on the pros and cons of that and 
other partitioning schemes.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       8 Dane Court Manor
                                                       School Rd
PGP: http://www.infracaninophile.co.uk/pgpkey         Tilmanstone
Tel: +44 1304 617253                                  Kent, CT14 0JL UK
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 372 bytes
Desc: OpenPGP digital signature
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20041229/e3418c70/signature.bin