Your plan is not nuts. As usual, there's more than a few ways to attack this based on what you're trying to achieve and how to protect your data.
First up, you can present a raw LUN to a VM using a "Raw Device Mapping". To do this:
- Present the LUN to the ESXi host (or host group, if you are going to use clustering/HA)
- Add a disk to your VM, select Raw Device Mapping, point at the LUN
- Rescan the SCSI bus inside the VM
- fdisk, mount and add to fstab, just like a normal disk.
Upside: fast to set up, fast to use, easy, can represent the disk to physical host if you find yourself needing to V2P down the track
Downside: you may lose some VMware-based snapshot/rollback options, depending on if you use physical or virtual compatibility mode
An alternate option is to create VMFS on the LUN to create a datastore, then add a VMDK disk to the VM living on that datastore.
- Upside: it's Storage vMotion-friendly if you ever buy a license to use it. This allows for hot migration of VMDK disks between LUN's and even SAN's.
In both cases, you're in a similar risk position should VMware or your VM eat the filesystem during a failure; one is not drastically better than the other although what recovery options will be available will be quite different.
I don't deploy RDM's unless I have to; I've found they don't buy me much flexibility as a VMDK (and I've been bitten by bugs that made them impractical when performing other storage operations (since fixed - see RDM section in that link))
As for your VM, your best bet for flexibility is to store your fileserver's boot disk as a VMDK on the SAN so that you can have other hosts boot it in the case of a host failure. Using VMware's HA functionality, booting your VM on another host is automatic (the VM will boot on the second host as if the power had been pulled; expect to perform the usual fsck's and magic to bring it up as in the case of a normal server). Note, HA is a licensed feature.
To mitigate against a VM failure, you can build a light clone of your fileserver, containing the bare minimum required to boot and have SAMBA start in a configured state and store this on each host's local disk, awaiting you to add the data drive from the failed VM and power it on.
This may or may not buy you extra options in the case of a SAN failure; best case scenario, your data storage will require a fsck or other repair, but at least you don't have to fix, rebuild or configure the VM on top. Worst case, you've lost the data and need to go back to tape... but you were already in that state anyway.
Best Answer
The IPMI port operates independently of the OS. For convenience's sake you can think of the DRAC card as connecting to a simple switch that also connects to the actual NIC and to the outside world. There are a few ways to approach your configuration, depending on how you have ESXi set up:
1.) If the interface is already in use by VMW w/VLAN tagging then the best answer is likely going to be to go into the IPMI setup during POST (i.e. the "Hit Control-E in 5 seconds..." prompt) and set the shared interface to use a VLAN tag. You'll also need to configure the upstream switch to allow this VLAN.
2.) If you have VLAN tagging enabled on the ESXi interface but don't want to configure VLAN tagging on the IPMI interface then you can likely configure your switch to hand off untagged frames to a given VLAN (also known as a native VLAN).
3.) If the interface isn't otherwise using tagging then configure the IPMI port to have an IP in the same subnet.