Monday, January 24, 2011

Accessing multiple local HD's or RAID with ESXi 4.0

How to I get additional HD's to be recognized and used by ESXi 4.0.

When I purchased my system I had two 2TB HD's, but when I installed ESXi it only recognized one of them. I'm happy to get whatever number of drives that I need (I have a four bay SATA in my Dell T310).

What are some options? RAID? If so, is it supported. I guess I would need hardware instead of software since ESXi is so small.

The VMWare forums (where I've lived for the last two days) are a charlie foxtrot of outdated and conflicting info.

I want to utilize my T310, with 32 GB RAM, 2.8GHz quad core to run many lab Windows VM's. I don't need production level availability but I do want decent performance, even though it's in a lab environment.

A huge thanks to Jim B., Zypher, Helvick, and Jeff Hengesbach who posted answers to my earlier predecessor question on why ESXi was so sluggish.

  • ESX and ESXi can't see individual volumes larger than 2TB which you have to bear in mind. There is some useful discussion on this with regard to ESXi and Dell servers in this VMware Communities thread. The 2TB limit stems from the fact that even with V4 both ESX and ESXi are still constrained by SCSI2 limits. If you build a RAID pack that is bigger than 2TB you will have to split it into volumes that are smaller than 2TB for ESXi to be able to use them. Note that this 2TB limit also applies to the maximum virtual disk (VMDK) size that ESX\ESXi can currently present to a VM but that's probably not an issue for you at this stage.

    The simplest way to add storage in your case is simply to add the drive and then rescan the storage adapters (Under the Configuration->Storage Adapters Tab select Rescan). This should then allow you to create a new Datastore on the new drive (under the Configuration->Storage Tab select the Add Storage link and then select New VMFS Datastore). The downside of this approach is that you are creating silos of single drive Datastores which isn't good for resilience or performance.

    If you have a RAID controller in the T310 then you should be able to configure RAID using the RAID BIOS at boot (CTRL+C to get into the SAS6/iR BIOS if you have that , CTRL+R if you have a PERC, see below if you have neither). That will allow you to build the RAID pack from the drives you have attached but your options will depend on the type of controller you have. You can then carve that (again in the Controller BIOS) into a number of smaller volumes so ESX can detect and use the storage. The problem with this approach is that you will probably need to reinstall ESXi completely to take full advantage of it but it's a much better way to present storage to ESX\ESXi.

    Dell's RAID controllers have some limitations and in order to implement a hardware RAID5 your choices are limited to the PERC-6i, H200 or H700 controllers. The SAS 6iR only supports RAID 0 or RAID 1. If you want other options you'll have to buy a 3rd party controller that is compatible with both ESXi and the T310. The VMWare Hardware Compatibility Guide is useful for finding this sort of thing. The Community Support site lists things that are not actively supported but have been reported to work.

    Shawn Anderson : Here is what I see on the HCL intro page. "NOTE: IDE RAID and SATA RAID are not supported for the VMFS file system." My T310 is a 4 bay SATA. Am I hosed here? My goal is to get higher IO so that I can run multiple Windows VM's without sluggishness. Am I reading this wrong? Do I have other options besides RAID, like having multiple discs (SATA) that ESXi can use simultaneously?
    Helvick : That statement doesn't mean it doesn't work (it does) just that VMWare don't support VMFS on SATA RAID. If you are using ESXi with its free licence then their active support isn't as important as knowing something will work. The Community support site is useful for scenarios like yours and the ESX Whitebox HCL [ http://www.vm-help.com//esx40i/esx40_whitebox_HCL.php ] is another unofficial site with useful pointers to configs that work.
    From Helvick

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