In-Depth

The State of vSphere Virtual Volumes

Testing is ramping up, and adoption in production environments has been steady, if not spectacular.

It's been more than a year since VMware formally announced vSphere Virtual Volumes (VVols) and nine months since the release vSphere 6.0, which allows for the use of VVols. I'e written a few articles on VVols for Virtualization Review, and helped with the Taneja Group's market landscape report on storage vendors' implementation of VVols. To follow up, I reached out to a few storage vendors to see how they thought VVols was doing since its introduction.

What Are VVols?
For the uninitiated, a bit of primer on VVols is in order. VVols is a new construct for the storage of VMware virtual machines (VMs). It radically changed the way VMs are stored on, and consume, storage. No longer do LUNs and NFS shares need to have attributes such as performance and protection levels assigned to them, then have VMs assigned to them in order to use these attributes.

Instead, VVols allows the capabilities of the underlying attached storage to be surfaced up directly to vSphere; VMs can have storage provisioned for them directly and in real time, based on the capabilities required, rather than being indirectly based on the capabilities of the LUN or share. This allows for storage to be used more efficiently and for VMs to be created quicker and with the exact attributes needed. Basically, VVols allows for VM-centric storage. For a fuller explanation of what VVols is and what it offers, see this article.

As of mid-December, there were 13 storage companies on VMware's hardware compatibility list (HCL), providing VVols enabled storage arrays: DataCore, DELL, EMC, Fujitsu, Hitachi (HDS), HP, Huawei, IBM, NEC, NetApp, NexGen Storage, SANBlaze and Tintri. Each one of these vendors surfaces up the capabilities from their VVol-enabled arrays to vSphere. One of the interesting aspects of VVols is that VMware allows the vendors a great deal of latitude in what capabilities they surface up. For example, HDS surfaces up a cost attribute.

The vendors I talked to mentioned that many of their customers are still in the experimentation stage with VVols. As a new storage construct, they're interested in it but not quite ready to deploy it in production for tier 1 applications. Others have shown interest in VVols, but have yet to deploy vSphere 6, which is required for VVols. A third group of companies is waiting for production level features, such as SRM, vROPs and replication, before they can consider it for deployment. That said, the vendors that I talked to said that customers using VVols have been impressed with its flexibility and reliability.

Hitachi
To illustrate, let's dive into the specifics what HDS, HP and Dell shared with me regarding VVols. Dinesh Singh, Solutions Marketing Manager at Hitachi Data Systems (HDS), told me that he is seeing customers starting to deploy VVols in test/dev systems, which is usually the case for new technologies for enterprise customers.

One of the blockers for VVol implementation is vSphere 5.5, which many customers are still using. Since HDS first released its VVol implementation they've had a few upgrades, including Hitachi Command Suite. This is its storage management console, which can now be used to create storage containers and define capabilities for block and file storage systems.

It also announced its all-flash arrays, which provides native VVol integration, making Hitachi effectively become the first AFA to provide VVol support. HDS is seeing broad interest in VVols, especially in the financials, telecom, and manufacturing sectors.

HP
HP was on board early with VVols; HP's Eric Siebert, who also curates vsphere-land.com, updated me on the latest developments on HP's implementation of VVols. Eric echoed what Dinesh said about enterprise customers adopting VVols, that it feels like the adoption of VVols is in line with other new technology. He also said more than 600 3PAR customers currently have the VVol VASA Provider enabled in the array.

The latest version of 3PAR OS supports multiple storage containers on a single 3PAR array, as well as multiple vCenter Servers. In addition, HP has increased scalability with support for 128,000 VVol objects. 3PAR is working with VMware as a design partner on the development of the next generation of VVols and the new VASA 3.0 specification. HP will again be the Fiber Channel reference platform for VASA 3.0.

Dell
David Glynn, Technical Solutions Engineer at Dell, updated me on the latest developments with VVols on EqualLogic. He said that their VVol lab on VMware's Hands-On Labs has been extremely popular. I can attest that this is a great way to get your hands dirty with VVols without having to invest in hardware or time in setting up an environment to run VVols.

Glynn said that because of their all-inclusive licensing policy, it's difficult to track how many of their customers are actually using VVols. He did say, however, that many of the conversations Dell is having with customers are along the lines of "I heard about this VVol thing. Help me understand it better, so I can plan for it," rather than "I'm about to deploy it."

This is not a surprise, as it's a big change in the storage stack, and in how environments are architected; many customers are just sticking a toe in the water to figure it out. Internally, they've been experimenting with VVols' rapid cloning capability, which offloads the deployment of new VMs to the SAN.

Cloning Around
The ability to clone a new VM in less than five seconds is very beneficial in an environment where VMs are short-lived. I expect this will lead to lower storage consumption, as fewer VMs will need to be kept in standby; after all, why keep a VM in standby when you know you can deploy it in a matter of seconds? The VDI environment will benefit greatly from rapid clone technology.

Glynn has also had a customer testing the resiliency of the VVols implementation. The vSphere API for Storage Awareness (VASA) plays a critical role in VVols, and the EqualLogic implementation has VASA running in a virtual appliance.

The customer was curious as to what would happen when the VASA went offline, and found that he would lose the ability to power on/off VMs and take snapshots. Satisfied by this, he took things a step further and asked, "What if I delete the VASA Provider?" and tested that for himself along with deleting the vCenter. While this should not happen in the real world, it was an interesting exercise, though with a very boring result. The EqualLogic implementation has the VASA provider storing the VMs' metadata on the SAN, so there's nothing of importance stored within the VASA Provider; it's just a communication channel. So once he deployed a new vCenter and a new EqualLogic VASA Provider, things continued as normal. (As a side note, each array provider will implement their VASA as they see fit, and for some the loss of the VASA Provider will be a problem.)

Dell will be adding VVols to their Compellent line in late 1H 2015. There will also be some updates on the EqualLogic implementation, but Glynn didn't detail exactly what they would be.

Testing the Waters
It looks like VVols is moving forward just as I expected: there are no huge surprises and customers are beginning to work with it. What has really impressed me is the support that VMware and its storage vendors are showing for this new technology. VMware has made VVols a feature, without an additional cost, in almost all of their versions of vSphere. Furthermore, VMware has spent a fair amount time educating their customer base about the power of VVols; folks have been blogging and speaking about it enthusiastically for the past year.

All of the storage providers that currently have VVols enabled arrays are providing that functionality for free, and many support VVols on their older equipment. Dell spent a considerable amount of time working with VMware to develop a Hands-On Lab for it. HP and others are working on the next version of VVols to remove some of the road blocks that are currently preventing the adoption of VVols.

Storage protocols are very sticky, and people tend to stick with what they know; however, the advantages of VVols are powerful, and VMware and its storage partners are making it as easy as possible to embrace this new technology. Over the next year or two, I predict that more and more IT departments will embrace the power of VVols; it would definitely be worth your while to invest an hour of your time in the Hands-On Lab, talk to your storage vendor, and start to work with it in your datacenter in order to see how it can drastically simplify your datacenter infrastructure.

About the Author

Tom Fenton works in VMware's Education department as a Senior Course Developer. He has a wealth of hands-on IT experience gained over the past 20 years in a variety of technologies, with the past 10 years focused on virtualization and storage. Before re-joining VMware, Tom was a Senior Validation Engineer with The Taneja Group, were he headed their Validation Service Lab and was instrumental in starting up its vSphere Virtual Volumes practice. He's on Twitter @vDoppler.

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