Admin Tips
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    - VMware ESX Server Tips
      - Resource Optimization
        Putting an ESX host in maintenance mode: known problems

Section(s): General, High Availability, Management, Resource Optimization
Published on Sep 09, 2008.
Last Modified on Aug 19, 2008.
Last Modified by Vincent Vlieghe.
Rated 1 out of 5 based on 1 votes.

This article describes how to avoid that the enter maintenance mode seems to be stuck

When doing maintenance on the ESX host in an Cluster, it is necessary to put it into maintenance mode so it can evacuate (or VMotion) all running guest without downtime. Sometimes, when putting an ESX host in maintenance mode, it will get stuck and not continue with the job.

Some tips to avoid this:

Make sure you disconnected all attached CD-ROM and floppy drives
Make sure the Virtual Machine is not connected to an internal switch only.
Make sure the VM is running on a shared volume, and not (for example) on local storage
It is possible that the admission control does not allow the ESX host to go into maintenance mode because all servers in the cluster are heavily loaded. You must change the HA (High Availability) setting on your cluster to allow virtual machines to be started if this constraint would be violated.

About Vincent Vlieghe

Vincent Vlieghe is a Technology Consultant for a company called Xylos. He has a number of certifications including MCSE, CCA, HP AIS, VCP and Softgrid CP. His main focus is on virtualization, Server Based Computing, Operating Systems and hardware/storage. In addition to his consultancy job, Vincent is also a trainer. You can find his blog at http://virtrix.blogspot.com/.