Nov
23

vVOLs – A Blast From The Past

I guess the first question is what is a vVOL? It’s not a rodent but it does involve pest control. The pest in this case are legacy vendors that tie policy to hardware instead of the work loads running on them. On twitter there was a post that found extremely funny,

Vols is a cancer-treating drug under clinical trial. Not for everyone.


Really smart people already blogged about what vVols is all about here and here. The jest of vVols of it is being VMware-aware, having fine grain management for VMDK’s. The concept is important for your storage vendor to support since no one wants to deal with 100′s of LUNS in ESXi cluster. It’s a lot easier to have a few giant volume\containers to throw all your workloads in from a storage management perspective. The downside of giant volumes is that you can’t tell who is peeing in the pool if you have performance problems and you can’t apply specific polices to your VM’s. The later really strikes home if you want to replicate one VM to your DR site. You end up having to replicate the giant volume across the WAN or go thru the man hours of cleaning up your mess. If you decide to clean up your mess, your basically changing your architecture to suite DR and not your workloads. This doesn’t tend to work out well too.

It only seems like legacy vendors care about vVols. Nutanix has no benefit from it from what I’ve read. There are three main parts that makeup the current known state of vVols, the storage provider, the protocol endpoint and the storage container.

Nutanix doesn’t really need to participant as Storage Provider since we are a integrated stack. Nutanix nodes have ESXi pre-installed and the Controller Virtual Machines help to form the Nfinity Distributed Files System(NDFS). NDFS allows Nutanix to set performance and availability at the VM level already.

Protocol Endpoint is already handled by Nutanix as well. This is 1/10 of reason why Nutanix can scale limitless. Nutanix is basically giving every VMDK a LUN. If your file is over 512KB a vDisk is created. A vDisk allows VMDK’s to span across multiple hosts. This very important since we use local storage to keep as much traffic on the speedy server bus rather than going out to clogged switch/SAN fabric. The performance of block and the easy of use of a file system.

Storage Container, same thing, we have that. In the UI of Nutanix you can create containers. Most of customers rock and roll to one giant one for the most part since there is no performance penalties from doing so.

So vVols is good if you Storage Vendor needs it but it seems like catch up to me. In a couple of months when Nutanix launches support of KVM, we already be rocking and rolling the goodness which is the Nfinity Distributed Files System. Therefore KVM will get vVols too!

DON’T BE RULED BY THE LUN, SET YOUR SELF FREE

Comments

  1. It would be nice to show us some screenshots from the UI of Nutanix, in one of your next blog posts… -:) Cheers.
    Vladan

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