With a new scalability server, a boot server is also installed. The new boot server does not take responsibility for target computers already assigned to another boot server in the subnetwork. Each boot server is responsible for a specified set of target computers only. The DSM Manager determines the set of target computers.
All boot servers observe PXE requests in their subnetwork, but they immediately reply only to requests of machines belonging to their own set of target computers. Requests from other machines are answered only after a certain number of retries and after a certain amount of time. The number of retries and the time to wait can be configured. More than one boot server may send such a default response.
A target machine receiving one or more default responses will choose one of the replying boot servers and establish a connection. This usually is the boot server that replied first.
A new target (not yet assigned to a boot server) will be fetched by that boot server.
A target already assigned to a different boot server will be reassigned to the new boot server. If there is an activated or pending installation order for the target and the required OS image is not available at the new boot server, the installation order is canceled.
The following configuration policy parameters under the DSM, ScalabilityServer, OSIM, ManagedPC, Server node change the behavior of a boot server with respect to other boot servers in the IP subnetwork:
Indicates whether the boot server uses an Answer Control List (ACL). Valid values are:
If Use ACL is set to “0”, the boot server must be the only boot server in its IP subnetwork because it answers all PXE requests immediately.
If Use ACL is set to “1”, the boot server immediately answers PXE requests of assigned targets only, that is, the boot server uses an ACL.
PXE requests from other target machines will be answered only after a certain number of retries has been seen and after a certain amount of time has elapsed since the first request.
If Use ACL is set to “2”, the boot server immediately answers PXE requests of assigned targets only, that is, the boot server uses an ACL, but it does not answer to unknown targets.
Default: “1”
Number of retries before a boot server sends a default reply to the PXE request of a target not assigned to it.
Limits: “1” to “4”
Default: “3”
Note: Only evaluated if "Use ACL" is “1”.
Number of seconds to wait before a boot server sends a default reply to the PXE request of a target not assigned to it.
Limits: “3” to “56”
Default: “10”
Note: Only evaluated if "Use ACL" is “1”.
The following table shows corresponding DiscoveryRetriesBeforeAnswer and DiscoveryTimeoutBeforeAnswer values:
|
DiscoveryRetriesBeforeAnswer |
DiscoveryTimeoutBeforeAnswer |
|---|---|
|
1 |
2 |
|
2 |
8 |
|
3 |
20 |
|
4 |
40 |
Any of the boot servers in an IP subnetwork can take responsibility for a PXE target. Therefore, it is recommended you store the needed OS and boot images on any of the boot servers in the subnetwork.
Delay PXE Response for Known Target:
The number in seconds for delaying the PXE Response from Boot Server to known (managed) PXE target.
Only if UseACL = 2
Limits: 0 to 28
Default: 0
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