If you have not yet updated to vSphere Update One, this post is for you to avoid the purple diagnostic screen of death with the error “COS Panic: Int3 @ mp_register_ioapic ” when upgrading from ESX 4.0 to 4.0 U1 after a reboot. ( Specifically if you are using HP’s insight management agents in the COS. )
See KB Article 1016070 for the latest.
Basically SHUT DOWN all HP COS agents before upgrading. This is only for ESX and not ESXi since there is no COS in ESXi. You should also examine 3rd party agents and plugins for compatibility in the lab before upgrading in production. For example, EMC storage viewer is broken with vSphere Update One, slated to be fixed in the EMC 2.1 release.
Make sure to read all the release notes and manual before attempting the upgrade, and have backups of course:
The vSphere Update One release notes:
http://www.vmware.com/support/vsphere4/doc/vsp_vc40_u1_rel_notes.html
The vSphere Upgrade Checklist here:
http://www.vmware.com/files/pdf/vsphere-migration-prerequisites-checklist.pdf
The vSphere Upgrade guide here:
http://www.vmware.com/pdf/vsphere4/r40/vsp_40_upgrade_guide.pdf
As any new items pop up, we will update this post.