LinuxSA Mailing list archives

  From: Mark Newton <newton@atdot.dotat.org>
  To  : Mike Earnshaw <mearnshaw@bigpond.com>
  Date: Wed, 16 Jun 1999 22:07:11 +0930 (CST)

Re: Bootdisk in RH6

Mike Earnshaw wrote:

 > In the section regarding the /dev I used the cpio program to copy the /dev
 > of the system into a 'new' directory. I was amazed at the number of devices
 > there are. From the HOWTO it says you can delete the SCSI block devices if
 > your system does not have them to preserve 'inodes'.

Hardly necessary unless your root filesystem is tragically under-provisioned.

 > Two things occured to me here:
 > 1. What is/are 'inodes' (are they similar to directory entries in FAT?,
 > where you can only have 512 entries in a root partition)

Each unique disk object is represented by an abstraction called an
"inode", which the kernel can read into memory and use to find the
file and perform operations on it.  It contains file statistical and
management data followed by a hierarchical data structure which lists
the disk block numbers utilized by the disk object (in cases where the
object actually has blocks allocated to it: Plain files and
directories).

Inodes are created when you build the filesystem (on most systems,
anyway - IRIX's XFS creates them on-demand).  If you run out you can't
create any more filesystem objects.

 > 2. With the 'character devices', what is/are the ones I must have on a
 > repair disk?

You may as well leave them all there.  "df -i" tells you how many
free inodes you have per filesystem;  I'd suspect you have several
thousand of them per partition.

    - mark

--------------------------------------------------------------------
I tried an internal modem,                    newton@atdot.dotat.org
     but it hurt when I walked.                          Mark Newton
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