EMC as a best practice recommends a Host be giving access to only one storage group however LUNs can be members of multiple storage groups, When booting from SAN the Host needs exclusive access to the Boot lun so for EXS clusters we must create storage groups for each host to contain the boot LUN and then add every lun that is a shared datastore into the storage groups as well to allow the Hosts to share access to them. When adding the Luns to the storage group they are given HostIDs, in a large dynamic cluster with multiple Host and a large number of datastores it is difficult to ensure that the HOST IDs match accross each Host. I have seen threads that suggest the HostID is only critical when using RDM luns, however the VShpere storage guide recommends keeping these IDs consistent.
1) should we make every effort to keep these IDs consistent accross each Host even if we are not supporting RDM's? With the latest versions of vShpere 5.0 / 5.1 is this not a big concern?
2) Any recomendations from an operational perpesctive to ensure during LUN provisioing that Host IDs added into storage Groups are consistent?