DRS question.
We have recently added a new host to our VMware 5.5 cluster. Currently, we have turned off DRS to make sure no VM being migrated to the new host.
Besides turning off DRS at the cluster level, is there a way we can prevent any VM from being moved into the new host?
We want the DRS option to be available only for the previous hosts to load balance each other until the new host is fully in production.
Thanks.
Besides turning off DRS at the cluster level, is there a way we can prevent any VM from being moved into the new host?
We want the DRS option to be available only for the previous hosts to load balance each other until the new host is fully in production.
Thanks.
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No, they will be moved.
What are you trying to do?
If the host is not fully in production, it should not have been added to the cluster! It should be tested first, and then moved finally into the Cluster for Production.
You will also need to disable HA, because in the event a Host Crashes, VMs will be restarted on the new host.
Also remember DRS is not a load balancer, it moves a VM, if the current host cannot satisfy it's resources it requires e.g. CPU and Memory.
and if you leave DRS ON, and set to MANUAL, no VMs are going to move anywhere, unless you manually do something.
What are you trying to do?
If the host is not fully in production, it should not have been added to the cluster! It should be tested first, and then moved finally into the Cluster for Production.
You will also need to disable HA, because in the event a Host Crashes, VMs will be restarted on the new host.
Also remember DRS is not a load balancer, it moves a VM, if the current host cannot satisfy it's resources it requires e.g. CPU and Memory.
and if you leave DRS ON, and set to MANUAL, no VMs are going to move anywhere, unless you manually do something.
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Sorry that I did not make the question clear.
We add a new host to a cluster, move a group of VMs into this new host. We do not want any more VM being moved as a result of DRS.
Besides turning off DRS at the cluster level which impacts the previous hosts in the cluster, is there a better way to do it?
Thanks.
We add a new host to a cluster, move a group of VMs into this new host. We do not want any more VM being moved as a result of DRS.
Besides turning off DRS at the cluster level which impacts the previous hosts in the cluster, is there a better way to do it?
Thanks.
What we do, if you are trying to build confidence in your new host, is we set DRS ON and MANUAL....
So, this will stop any VMs automatically moving around your cluster, and then run the DRS review, manually move VMs using vMotion (a human does this) to satisfy DRS conditions and CPU and Memory pressure - if any exists...
and we then only move low priority VMs to test this new host, until we are happy all is working well, to set DRS back to AUTOMATIC, Aggressive.
How long you test and build confidence in this new host is based on your Test Plan.
So, this will stop any VMs automatically moving around your cluster, and then run the DRS review, manually move VMs using vMotion (a human does this) to satisfy DRS conditions and CPU and Memory pressure - if any exists...
and we then only move low priority VMs to test this new host, until we are happy all is working well, to set DRS back to AUTOMATIC, Aggressive.
How long you test and build confidence in this new host is based on your Test Plan.
Another option, instead of disable DRS, is let it Fully Automated and change the migration threshold to a level different than the level 3 (default). For example, changing the migrating threshold to level 1 (conservative) will only apply recommendations that must be taken to satisfy cluster constraints like affinity rules and host maintenance.
ASKER
Thanks, guys.
I am not familiar. Would you provide instruction on how to set DRS to different level?
Thanks.
I am not familiar. Would you provide instruction on how to set DRS to different level?
Thanks.
ASKER
For of all, thanks for your useful suggestions.
Currently, there are 5 VMs in the new host and DRS is set to off.
To see the threshold settings, I will have to enable DRS again. Other VMs will be moved to the new host as it has more resources.
Is there a way that I can enable DRS but exclude the new host to be involved?
If I enable DRS, set automation level to MANUAL, migration threshold to MEDIUM, I think no migration will occur, right? What is the different between doing this and disable DRS?
Currently, there are 5 VMs in the new host and DRS is set to off.
To see the threshold settings, I will have to enable DRS again. Other VMs will be moved to the new host as it has more resources.
Is there a way that I can enable DRS but exclude the new host to be involved?
If I enable DRS, set automation level to MANUAL, migration threshold to MEDIUM, I think no migration will occur, right? What is the different between doing this and disable DRS?
If I enable DRS, set automation level to MANUAL, migration threshold to MEDIUM, I think no migration will occur, right?Yes, only recommendations will be generated but no automatic migration will occur.
What is the different between doing this and disable DRS?The difference is that on DRS enable in manual mode, the DRS will evaluate the resource utilization of your cluster and made migration recommendation. With DRS disable, no evaluation or recommendation will be generated.
Again, I believe that the best scenario for you is create Affinity Rules, that will allow DRS run in Fully Automated mode and avoid unwanted virtual machines be migrated to the new host.
Disable DRS and it does not function.
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