Comments on: Recommended Detailed Material on RDM’s

By: Laura Brown

Laura Brown — Sat, 21 Jan 2012 20:27:39 +0000

Hello,

I am studying for the VCP 410 and I came across your blog. This is an excellent post! It really helped me understand how RDM works. Thank you so much.

By: Henri

Henri — Wed, 16 Nov 2011 17:37:40 +0000

Excellent article, however “I would recommend Physical Compatibility mode.” for cluster in a box? VMware seems to say virtual RDM or vmdk only for cluster in a box, in the MSCS vsphere 4.1 white paper.

By: EV10 Notes: 3-node MSCS Cluster-across-Boxes on ESX 4.1 | Jonson Yang

EV10 Notes: 3-node MSCS Cluster-across-Boxes on ESX 4.1 | Jonson Yang — Wed, 16 Nov 2011 15:48:29 +0000

[...] Detailed Material on RDM’s http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/ [Jonson] detail info on RDM, [...]

By: Raw Device Mapping – RDM in vSphere 4 and 5 Resources and Experiences « Virtual Noob

Fri, 28 Oct 2011 17:20:04 +0000

[...] http://www.vmware.com/pdf/vsphere4/r41/vsp_41_esxi_server_config.pdf (Lots of references to RDM) http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/ (Lots of Good stuff) [...]

By: Joep Piscaer

Joep Piscaer — Sun, 16 Oct 2011 12:22:17 +0000

Hi Jonathan,
There simply isn’t a way to use a partition as an RDM. RDM’s just work with LUNs (or disks). Also, local disks aren’t supported.

By: Joep Piscaer

Joep Piscaer — Sun, 16 Oct 2011 12:21:56 +0000

Hi Jonathan,

There simply isn’t a way to use a partition as an RDM. RDM’s just work with LUNs (or disks). Also, local disks aren’t supported.

By: Jonathan Lundquist

Jonathan Lundquist — Wed, 12 Oct 2011 15:48:25 +0000

Very nice article. First one I’ve found which catagorically states partitions cannot be RDMd. That explains why I can’t find any way to do so ;-(. I want to use half an SSD for ESXi and pass half of it to a client VM for use as ZFS cache.
I thought I’d just pass the whole LUN and be smart enough not to touch the ESXi partition from the client, but a lock ESXi claims prevents that.
As you’re now my acknowledged expert, could you offer any suggestions to work around this?
Thank you!

By: ESXi Accessing LUNs: Physical or Virtual Mode? - Admins Goodies

ESXi Accessing LUNs: Physical or Virtual Mode? - Admins Goodies — Wed, 17 Aug 2011 01:01:28 +0000

[...] nothing is written to the LUN other than the guest filesystem information even in virtual mode (see http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/). I would suspect that, since you’re looking for the capability to mount the RDM LUN [...]

By: VCAP-DCA Study notes – 1.1 Implement and manage complex storage | www.vExperienced.co.uk

Mon, 21 Mar 2011 09:41:15 +0000

[...] Piscaer has written up a good summary of RDMs, and from that article –“RDM’s gives you some of the advantages of direct access to a [...]

By: ESXi Accessing LUNs: Physical or Virtual Mode?

ESXi Accessing LUNs: Physical or Virtual Mode? — Sun, 21 Nov 2010 04:25:42 +0000

By: VMware Raw Device Mapping (RDM) Volume, Detailed Material «

VMware Raw Device Mapping (RDM) Volume, Detailed Material « — Fri, 22 Oct 2010 23:17:14 +0000

[...] http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/ [...]

By: Daniel Hernandez

Daniel Hernandez — Fri, 17 Sep 2010 04:04:55 +0000

How many RDM per virtual machine i can assign??
i have vsphere 4 update 1, i try assign 3 RDM but i cant.

do you know???

By: Microsoft Clusters in Virtual Environment | Devoted to VMware

Microsoft Clusters in Virtual Environment | Devoted to VMware — Fri, 27 Aug 2010 18:16:07 +0000

[...] http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/ [...]

By: habibalby

habibalby — Fri, 04 Jun 2010 05:27:42 +0000

Hello,

I’m currently on the process of redesigning my MSA1000 that connected to 4 vSphere hosts and i have MSCS SQL 2000 and Exchange 2007.

I’m migrating the entire VMs to a new iSCSI SAN based on StarWind as a Temporary till I swapped everything in the MSA1000 and reconfigure it to host my VMs.

I’m wondering about my SQL and Exchange which using RDM LUNs, could you please give me some tips and tricks to migrate my RDM to the new iSCSI Storage, recreate them on the MSA1000 and re-migrate the VMs back to the MSA1000.

Thanks once again,
Habibalby

By: Upgrading SAP Finance in a virtual environment (RDM vs. VMFS) « Documenting a virtualization project

Thu, 20 May 2010 14:01:06 +0000

[...] http://www.virtuallifestyle.nl/2010/01/recommended-detailed-material-on-rdms/ [...]

By: Mika

Mika — Wed, 28 Apr 2010 16:33:05 +0000

Matt,
Can you (or someone else) explain how you attached a 10TB RDM to vSphere, when the stated maximum is 2TB?
Is this possible but unsupported?
Mika

By: Joep Piscaer

Joep Piscaer — Tue, 13 Apr 2010 07:00:43 +0000

I believe this is stated in either the iSCSI or the FC SAN configuration guide.

By: Andi

Andi — Mon, 12 Apr 2010 18:54:27 +0000

Joep, thanks for your reply. I’m trying to understand how it works. That’s what I thought and told to my client in the first place… but is there any official document that states this?

By: Joep Piscaer

Joep Piscaer — Tue, 23 Mar 2010 23:21:29 +0000

Andi: If you use a physical compatibility mode RDM, make sure to configure the LUN with settings for the Guest OS, i.e. Windows 2003. Don’t set these LUNs to any VMware-format, as VMware does not interact with these LUNs. For any LUNs that contain the VMFS filesystem, configure as VMware LUNs. For Virtual Compatibility mode, set according to your SAN vendor’s recommendation.

By: Andi

Andi — Tue, 23 Mar 2010 20:04:08 +0000

In Physical Compatibility mode, with a Windows 2003 Cluster, the RAW LUNs presented to the ESX are configured with VMWARE Host Type or W2003 Host Type?

I have constant fail overs due to heavy IO, and the RAW LUNs are in the same HostGroup as the rest of the LUNs, so, they are all configured as “VMWARE” LUNs.

The fact is, those RAW LUNs are accessed exclusively by the MSCS, so I understand that they MUST be configured as “Windows 2003 Cluster” LUNs. Is this correct? Wich HostType is correct for a RAW LUN in Physical Mode?

Thanks in advance.-