If using the new 4.1 "vm to host" rules you can select for example that VMs in Vm-group-1 SHOULD run on Host-group-2. Here "should" is softer than "must", as in it will be allowed to run on other hosts, but my question is when this is allowed?
Is it in case of failure or is it in case of resource overcommit? That is, if hosts in Host-groups-2 for example are running 100% cpu all of them, will DRS move a "should-VM" to another host?
It is in case of resource overcommit because HA is not aware of preferential rules. VMware vSphere 4.1 HA and DRS technical deepdive, page 137.
Regards, Robert
It is in case of resource overcommit because HA is not aware of preferential rules. VMware vSphere 4.1 HA and DRS technical deepdive, page 137.
Regards, Robert
Robert van den Nieuwendijk wrote:
It is in case of resource overcommit because HA is not aware of preferential rules.
Nice, so the rule means that as hardware load permits - let the vm-group run on a certain host-group, but if host-group is overcommited it is allowed to move? Perhaps it should try to move out most other VMs first to let the VMs in the rule stay?
VMware vSphere 4.1 HA and DRS technical deepdive, page 137.
Book is ordered, but have not yet arrived. : )
Take a look at http://pubs.vmware.com/vsphere-esx-4-1/wwhelp/wwhimpl/js/html/wwhelp.htm#href=resmgmt/c_using_vm_hos...
This describes the "must" and the "should" rule and what is allowed/denied when setting them.
André
Robert van den Nieuwendijk wrote:
It is in case of resource overcommit because HA is not aware of preferential rules.
Preferential rules is the "should" ones, correct? From the manual HA is aware of the "must" rules.
preferential is should indeed, "must rules" are the only ones to which HA will adhere.
Duncan
Yellow-bricks.com | HA/DRS technical deepdive - the ebook