Creating an RDM boot OS

[gselby]

Hi there,

I currently have a large VMFS volume on our SAN that stores all the boot OS images and templates. I would like to move away from this setup and present a seperate LUN for each boot OS. I'm already using RDM for the data drives and it works a treat! I was wondering is there any reason why I cannot use RDM for the boot OS? Obviously I won't be able to create images from templates anymore but I can copy an OS template within the SAN so that's not an issue.

Are there any implications for VMotion by creating RMD boot volumes?

Does anyone know what the maximum number of LUNS VI3 can handle?

I'm running ESX 3.5

Thanks in advance,

Glenn.

[vmroyale]

"With ESX Server 2.5, you could not use boot from SAN together with RDM. With ESX Server 3.x, this restriction is removed." - taken from Chapter 5 of the Fibre Channel SAN Configuration Guide at

I use VMotion with RDMs all the time - it works great.

Max LUNs is 256 - check the Configration Maximums for 3.5 at

Good Luck!

[gselby]

Thanks for the quick responce.

It appears that the doc you sent me is about booting ESX servers from the SAN which I already do. What I would like to do is boot VMs from the SAN. Do you know if that is possible?

Thanks

[azn2kew]

Theoretically, it supports 256 LUNs but each VM has redundant path which than becomes 128 LUNs by far.

"Reading Is Fundamental" There is no limit to education

[azn2kew]

You can check out Data Core product which allows Windows VMs systems to boot from SAN or iSCSI.

"Reading Is Fundamental" There is no limit to education

[vmroyale]

I'm using ESX 3.0.2 here with a FC SAN.

Here is a test I did:

I was unable to create a VM with a non-VMFS formatted datastore.

I was able to create a VM with an existing VMFS datastore, add the RDM to the VM and then delete the existing VMFS-based disk.

What was left was a VM with one disk - a Mapped Raw LUN.

I was able to install Windows on this disk and everything works fine.

The question I can't answer for you (or find documentation on) is whether or not this is a supported configuration.

Good Luck!