While attempting Distributed Power Management (DPM) with my vSphere 5.0 DRS Cluster, the hosts appeared to hang indefinitely when Powering on out of Standby Mode.
The host boot sequence appeared to be stuck after the iSCSI module loaded successfully.
At first, I thought that maybe the NIC cards were no longer supported with vSphere 5.0 for Wake-on-LAN (WoL). However, I persisted in troubleshooting further.
I noticed that when I removed the Software iSCSI Initiator from one of my hosts, the problem disappeared. This behavior confused me a little until I used my Handy Consultant’s Field Guide (google.com 🙂 ), and I saw a blog post from Eric Siebert.
Apparently, the Software iSCSI Initiator takes a fairly long time to verify targets during the boot sequence. This explains the problems I experienced. After installing the latest build of ESXi that includes the Software Initiator fix, the problem disappeared.
Thanks Eric Siebert for the great info!