I have one VM per cluster that needs a fixed multipathing policy to access an RDM as per vendor requirements. The other VMs would normally be using round-robin as per best practices
I need this VM to be able to be protected by HA, so that all hosts in a cluster should be able to access the RDM using a fixed multipathing policy. But all other datastore access should use round robin.
Is this possible and are there any caviats / gotchas?
Multipathing policy is always set on a per LUN basis anyways (not per VM).
are there any negative impacts then to having different multipathing policies in use on different LUNs used by the same HA / DRS cluster?
No, not that I would know of. Basically the best option - if supported by the storage - is Round-Robin for most use cases, except e.g. MSCS as in your case.
André
What array do you have
Always double check your array vendor supports round robin otherwise you'll cause more problems on your array