Linux System Administration

Slightly more tedious and complex than adding a disk drive to other microcomputer systems.
Hints for Splitting Linux Across Two Disks

UNIX versions designed for microcomputers tend to assume that such systems have a single disk large enough to accommodate all of the filesystems that it will use. If what you actually have is a smaller amount of space on each of two disks but not enough on either one to hold all of UNIX, there is usually no built-in way to install the operating system anyway. However, a procedure like the following will usually be successful:

  • Install a minimal operating system on the partition on the first disk.

  • Add the partition(s) from the second disk to the system.

  • The general strategy is to create symbolic links to the partition on the second disk to allow the operating system to be split across them. This can mean copying some directories to the second disk after installation and then creating links in the original location, as in this example (/d2 is the mount point for the partition from the second disk:

# cd /d2
# tar -cvf - -C /usr/lib terminfo | tar -xvpf -
# rm -rf /usr/lib/terminfo
# ln -s /d2/terminfo /usr/lib/terminfo
  • Alternatively, if you know or can determine the location for an operating system component before installing it, you can pre-set up the symbolic link, then install that component, and the files will be written to the right location to begin with. For example, the following commands will cause the manual pages to be written to the second disk:

    # mkdir /d2/man
    # chown bin /d2/man; chgrp bin /d2/man
    # chmod 755 /d2/man
    # ln -s /d2/man /usr/man
  • When selecting components to move, avoid placing anything required to boot the system on the second disk.

  • Continue this process until everything you want is installed.

Reprinted with minor alterations by permission from Essential System Administration ---Edition 2, copyright (C) 1995, O'Reilly and Associates, Inc. For orders and information call 800-998-9938 or 707-829-0515.

Æleen Frisch manages a very heterogeneous network of Linux and other UNIX systems and PCs. After finally finishing the second edition of Essential System Administration, she has gone back to her true calling in life, pulling the string for her cats, Daphne and Sarah. She can be reached via e-mail at