frankdenneman Frank Denneman is the Machine Learning Chief Technologist at VMware. He is an author of the vSphere host and clustering deep dive series, as well as podcast host for the Unexplored Territory podcast. You can follow him on Twitter @frankdenneman

VMware Fault Tolerance and DPM

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Some requirements of the design I am working on is to be as “green” as possible and to offer the highest level of redundancy for business continuity. Enter VMware Fault Tolerance (FT) and Distributed Power Management (DPM)! When mixing multiple features, the requirements of one feature can have impact on- or even worse becomes a constraint of the other feature.
DPM works together with DRS to VMotion virtual machines onto fewer ESX host servers when the resource demand drops below a specific threshold. In the current release of vSphere, DRS does not consider the FT-enabled virtual machines during load balancing operations and DRS will not migrate FT-enabled virtual machine automatically, because of this DPM cannot power down these hosts until the administrator will manually VMotion the primary or secondary virtual machines to another ESX host server.
Fortunately when enabling DPM on the cluster, you can disable DPM at ESX host level. Due to the current limitations of DRS with VMware Fault Tolerance, it is recommended to disable DPM on at least two ESX server host to act as host for FT-enabled virtual machines.

frankdenneman Frank Denneman is the Machine Learning Chief Technologist at VMware. He is an author of the vSphere host and clustering deep dive series, as well as podcast host for the Unexplored Territory podcast. You can follow him on Twitter @frankdenneman

6 Replies to “VMware Fault Tolerance and DPM”

  1. DPM is a gimmick. In the data center you have already paid for and are running power and cooling and facilities: turning of a few servers saves some watts and cash, but it’s miniscule.
    The better option, which I was going to demo @ VMworld until I was sent a Dear John letter, is to use your investment as much as possible.
    If you want to be green in the data center, you probably need a new type of data center that has PUE of less than 1.5. DPM will have zilch effect on your PUE.

  2. Re: DPM is a gimmick from Steve.
    I guess to each his own. But I did feel that the comment was a little one-sided. Just because large data centers are built the way you describe doesn’t mean that the rest of the world cannot benefit from DPM.

  3. Keep watching VMware, they are aware that DPM is not a panacea and are working with various vendors to make DPM more robust. Eventually you will be able to power down entire rows and turn off the PDU’s and AC units feeding those rows for significant power savings.

  4. I somewhat agree with Stevie but in the future when the ability to recoup the cost of un used power in a datacenter is the norm then DPM will be a must have. also i think sometimes these things are about perception. If my bosses think they are saving money then they will buy the feature. Having said that it works fine albeit the issue Frank has highlighted. if only DPM was more DRS friendly, here’s hoping!

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