[H-GEN] Quick Question :)

[ben.carlyle at invensys.com]

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G'day






"3 Blokes" <gerbil at bigpond.net.au>
Sent by: Majordomo <majordom at caliburn.humbug.org.au>
18/02/03 13:14
Please respond to general

 
        To:     <general at lists.humbug.org.au>
        cc: 
        Subject:        Re: [H-GEN] Quick Question :)
> On a side note, The server I was speaking about has a 20 Gig HDD in it 
which
> is needed elsewhere, i'm going to use Driveimage to image it to a 4Gig 
HDD I
> have sitting around, so here's my question, will linux 'freak' out when 
it
> boots up and finds all it's partitions have gotten alot smaller?

... only if you screw up the filesystems :)

If the relevant filesystems are complete and intact, and they exist on the 
same devices[1], then you're ok. Your drive reshuffler program -must- know 
about the filesystems you have under linux, and presumably must also know 
how to locate and rearrange the free space associated with each 
filesystem. Make sure that your filesystems are in the set supported by 
this application, as the standard linux filesystems these days include the 
traditional ext2 as well as ext3, reiser, etc.

The boot process of the linux kernel will generally follow this scheme:
1) Mount the device hard-coded into the kernel image as the root 
filesystem. This device must be the same in the new hardware configuration 
as it was in the old, or nothing will start. Actually, the technical 
details of this seem to have changed since I last played in this area so 
others[2] might be able to enlighten you more.
2) Read /etc/fstab[3] and for each device listed as being automounted the 
operating system will mount them. If these devices change you will have to 
edit /etc/fstab, which you may be able to do from the root filesystem 
without anything else being mounted... or you may have to use a rescue 
disk to modify after the hardware configuration has changed.

Anyway. There's nothing above that level that really cares how big the 
disks are, nor is there anything that cares much where the disks live. 
Once you've gotten that far you're probably ok. Also, don't forget your 
swap/tmp partitions if you have them ;)

Benjamin

[1] ie, the same ide/scsi slot with the same partition arrangement.
[2] humbuggers or google.
[3] Other unixes give this file different names... some things will never 
be the same


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