Apple Mac OS X Server (version 10.2.3 or later) - Manual (Page 520)

520 Chapter 12
If the mount point specified by path is directly bootable, you don’t need to specify image.
Examples:
m server3:/Images/OSX/ Jaguar:Jag_10_2.dmg
(points to the image file Jag_10_2.dmg in /Images/OSX/ Jaguar on the host server3)
m 172.16.12.20:/Images/OS_X/ Jaguar
(specifies a directly bootable mount point on a server identified by IP address)
The associated boot files (booter, mach.macosx, and mach.macosx.kext) and the property list
file (NBImageInfo.plist) must remain on the NetBoot server in the image.nbi folder.
Shadow Images
Many clients may read from the same system disk image, but whenever a client needs to
write anything back to its startup volume (such as print jobs and other temporary files),
NetBoot automatically redirects the written data to the client’s shadow image—a file hidden
from regular system and application software. The shadow image is what preserves the
unique identity of each computer during the entire time it is running off a NetBoot server
disk image. NetBoot transparently handles reading changed data from the shadow file, while
reading unchanged data from the shared system image. The shadow image is recreated at
boot time, so any changes made by the user to his or her startup volume are lost upon
restart. For instance, if a user saves a document to the startup volume, after a restart that
document will be gone. This behavior preserves the condition of the environment the
administrator set up. Therefore it is recommended that users have accounts on a file server
on the network to save their documents.
NetBoot creates an AFP share point on each available server volume and distributes client
shadow images across the volumes as a way of balancing the load for NetBoot clients. There
is no performance gain if the volumes are partitions on the same disk. See “Load Balancing”
on page 537.
NetBoot Files and Directory Structure
NetBoot gathers information about a client the first time the client tries to start up from the
NetBoot server. NetBoot stores this information in the file /var/db/bsdpd_clients.
LL0395.Book Page 520 Wednesday, November 20, 2002 11:44 AM