Why am I seeing it take 300s or more to fail a device-mapper-multipath path with a storage array using ALUA in RHEL 5?

Issue

• Servers connected to a storage array are seeing aborted commands and 300s SCSI command timeouts in /var/log/messages.
• We are experiencing storage path failures that take upwards of 300 seconds for device-mapper-multipath to start using the next path

• Errors similar to:

  Oct 24 22:53:57 example kernel: qla2xxx 0000:0f:00.0: scsi(4:1:32): Abort command issued -- 1 916a951 2002.
  Oct 24 22:53:57 example kernel: sd 4:0:1:32: timing out command, waited 300s
  Oct 24 22:53:57 example multipathd: /sbin/mpath_prio_alua exitted with 5
  Oct 24 22:53:57 example multipathd: error calling out /sbin/mpath_prio_alua /dev/sdfw