You can enable a multicast image server using the Mac server multicast asr command. Multicast asr can restore multiple clients simultaneously from one looping multicast of an asr disk image. An asr disk image is the same as a NetRestore image that you create using System Image Utility.
Each client can receive the NetRestore image at any time during a multicast of the image, and the client continues receiving the first part of the next multicast until the client receives the complete NetRestore image.
The server multicasts only one copy of the NetRestore image at a time, and all clients receive this copy.
If the server finishes multicasting the NetRestore image and a client is still requesting the image, the server multicasts the image again. Thus, using multicast asr to stream images to multiple clients doesn’t congest the network nearly as much as Network Install with multiple clients.
To enable the image server, use the asr tool with the -server flag and a correctly built image and plist file.
To start a multicast server for a specified image:
$ asr -source compressed image -server configuration.plistThe image doesn’t start multicasting on the network until a client attempts to start a restore. The server continues to multicast the image until the process is terminated.
To configure a client to receive a multicast stream:
$ sudo asr -source asr://hostname -target targetvol -eraseThe client receives the multicast stream from hostname and saves it to the client.
To overwrite an existing image, add -erase. Using -erase with -target indicates that an image should be overwritten when doing a multicast.
For information about asr, see its man page.