Planning for High Availability

Handling Printer Failures

In order to implement high availability of printers for an organization, you configure multiple physical printers on the same queue. The supervisor for different physical printers on the same queue may be one or multiple. If the physical printers configured on the same queue have different supervisors, then those supervisors need not run on the same node, so a node failure disabling one supervisor need not disable all the physical printers on a queue. Whether a supervisor is unavailable, or a physical printer is unavailable, a job in a queue will print on the first available physical printer.

A configuration where multiple supervisors run on different nodes is possible only in the DCE Extended Environment.

Printers attached to other hosts can become available from your host in the Basic Environment by creating HPDPS Gateway Printers. All printers created in one Basic Environment can become available on another host using these Gateway Printers.

Handling Node Failures

In order to implement high availability of the HPDPS servers, the administrator can set up redundant spoolers and supervisors on another node. The print persistent storage in /var/opt/pd can be placed on a shared file system. In case the primary servers become unavailable, then the redundant servers can be brought up on the alternate node. Using the same print persistent storage, the alternate servers can continue processing outstanding jobs.

A distributed configuration is another way to implement high availability. A distributed configuration is possible with a DCE Extended Environment. In the Extended Environment, HPDPS objects such as spoolers and printers created by any member of the DCE cell, are instantly available to the entire cell. For example, if a new printer is created with a DCE Extended Environment server, the name of the new printer is visible to every client in the cell and each client can immediately issue HPDPS operations to that printer. Consequently, one node failure does not stop the access to the new printer.