iSCSI LUN vs RDM LUN inside guest OS

azhukovamt — Thu, 05 Jun 2025 05:52:05 GMT

Hi Everyone,

Can I use iSCSI LUNs inside guest VM with software MS iSCSI initiator and MPIO ?

We are going to virtualize our file server. Several LUNs are connected to the fileserver.

We have custom backup and snapmirror scripts via sdcli for each LUN. I wouldn't like to do any changes, because it works.

Is it officially supported ?

I see only RDM solutions in many TRs/articles. My main purpose is 'don't change anything and easy migrate to VM'.

Software initiator/MPIO is working fine for me and I don't see reason to go with RDM.

If I will connect a iSCSI LUN as RDM, can I reconnect that later to another server via MS iSCSI initiator ?

Cisco UCS

ESX 5.5, VSC 4.2.1

guest OS: Win 2012, HU 6.0.2, Snapdrive 7.0, MS iSCSI initiator and MPIO, two paths via two fabric interconnects

Thanks

Re: iSCSI LUN vs RDM LUN inside guest OS

rwelshman — Fri, 11 Oct 2013 16:14:22 GMT

You can use iSCSI LUNs on a VMware guest - the MPIO might not work as before due to the virtualization of the network. But it should be ok, if you configure the VM with the same number of NICs / networks as the physical.

I'm not sure if you can easily switch between RDMs and iSCSI connectivity - probably simpliar to just stick with using iSCSI.

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iSCSI LUN vs RDM LUN inside guest OS

Re: iSCSI LUN vs RDM LUN inside guest OS