After configuring two printer as a class, schedule 10 printjobs one page each. 1-2 minutes before printing pull the plug on say printer 2. Start printing 1st job get sent to printer 1 and print second job gets sent to printer 2 which is not there It doesn't print as printer 2 isn't plugged in and sits there waiting. All the remaining jobs getting sent to printer 1. The problem is acknowledged upstream: http://www.cups.org/str.php?L1084
Judging from the upstream reaction, I guess Red Hat Enterprise Linux 4 is affected too.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2007-0475.html