With more enterprises virtualizing their servers and storage, storage management has become more complex, and storage admins who traditionally only had to worry about physical arrays now face challenges in other aspects of their infrastructure. In many ways, however, the latest virtual server storage developments are making storage management even easier with improved metrics and built-in monitoring tools. In this expert podcast, virtualization expert David Davis talks with Associate Site Editor Sarah Wilson about how the latest virtual server storage trends affect the job of storage administrators, and provides insight on how future developments may continue to change storage management in the future.
Let's start by talking about how virtualization has changed over the past few years. How has that impacted storage management?
David Davis: To me it immediately brings up the idea of the software-defined data center, or SDDC as VMware has coined it and heavily promoted it. With basic virtualization you can have a virtualized disk for each virtual machine, but now VMware and other vendors are really expanding that idea by creating virtual storage appliances, and they could potentially one day replace small NAS [network-attached storage] or SAN arrays, and I have no doubt that vendors like VMware and others will continue to advance those types of software-defined storage solutions in future revisions. And this idea that server virtualization can replace physical servers is now being taken to the next level, and virtualization will soon will be able to replace complete storage systems -- the traditional, hardware-based SAN arrays or NAS arrays in the data center.
So not only is VMware advancing and promoting that idea but there's so many other competing virtualization vendors and numerous third-party vendors that have their own virtualized storage solutions. And what's happening is you have a whole new product category. This new product category is something that storage admins will have to deal with, and not only with their traditional job of configuring the existing SAN and physical storage arrays in the data center, but they'll now have to manage what will become virtualized storage arrays that are running inside the virtualization layer. And this is similar to what happened with traditional physical server admins when virtualization came into the data center. Those physical servers were virtualized, and those physical server admins had to deal with virtualization if it wasn't their idea to introduce it and embrace it. So most storage admins will have to embrace virtualized storage solutions just like the physical server admins had to embrace server virtualization. And it's not going to stop there. Network admins will soon have to embrace virtualization as well, as there are more and more software network solutions on the market.
Would you say there are any other ways that server virtualization is changing the traditional role of storage admins?
Davis: Traditionally the storage admin just cared about the storage arrays; it was their job to manage the storage arrays and then provide storage capacity to the servers and the applications when needed. That storage was usually provided in the form of a SCSI LUN through Fibre Channel or iSCSI arrays. But now with storage and the virtualization layer becoming more intertwined, not only do they have to have a virtual server storage solution in the data center that they're going to have to manage, but the traditional physical storage arrays that they've been managing for some time are becoming more virtualization-aware. And this is a term that's become more popular lately as the storage arrays are starting to offer more and more integration.
So some examples of this -- one vendor allows their storage array to talk directly to the vCenter Server to gain information about what VMs are running on what LUN on the storage array, and through the storage array you can report statistics about I/Os per VM and much more. I/Os per VM is probably the most critical. And then from that you can make smart decisions, and especially empower the storage admin to know which VMs are causing the most traffic on the storage LUN so that the storage LUN could be reprovisioned or use a different RAID configuration, or those VMs could be moved to different LUNs. And that's the type of information that both storage admins and VM admins need to do their jobs more effectively. If your array supports technology like VMware’s vStorage APIs for Array Integration, or VAAI, some of the most time-consuming tasks like cloning or snapshots, those can be offloaded to the storage array and then done in seconds compared to 15 minutes or 30 minutes for a large VM. Let's say a clone is done through the traditional vSphere VMkernel. And then another VMware feature is called vStorage APIs for Storage Awareness, or VASA. With VASA the array can report back to vCenter latency and utilization statistics so that vCenter can actually make intelligent decisions about moving virtual server storage with features like VMware Storage Distributed Resource Scheduler.
So you've got this two-way communication. The hypervisor is talking to the array with VAAI, and then the array is talking back to the hypervisor and hypervisor management with VASA. This hypervisor and storage integration affects the storage admin because the storage admin has to become more educated about virtualization and be prepared to configure these types of storage integration features, understand them, see their benefits and then perhaps even be prepared to completely virtualize some piece of their traditional storage array at some point in the future.
Are there any developments that you think we might see, or that you hope to see in the future that would help manage virtual server storage?
Davis: I talked about some of these completely virtualized storage solutions, and what I'm excited about in the future -- one of them available today is VMware's virtual appliance or VSA -- that's a nice solution, but it's really targeted toward the SMB enterprise. I'm excited to see solutions from VMware and other companies that are similar in concept -- completely virtualized storage arrays that offer many more features and much more robust performance. And it's those types of solutions that I could see in the future replacing expensive SAN arrays and still offer similar performance that you would need.
I think that with SSD [solid-state drives] becoming so much less expensive, and with hypervisors becoming much more advanced, these completely virtualized storage arrays will soon become available and very likely even commonplace.
On the traditional storage array side, those physical storage arrays with SANs in the data center, I don't think those are going away any time soon. But what I'm excited about is virtualization-aware storage, as they're calling it. Basically more features built into those traditional storage arrays that allow them to talk to the virtualization management layer, and give them a much stronger integration, that API integration between the storage and the hypervisor, and even third-party capacity management and performance tools.
One more thing that I'm excited about and want to talk about is those server-side caching solutions that are going to take what you already have -- your traditional array and your traditional physical server with a virtual hypervisor on top, and then dramatically increase the performance and VM density between those. I think that's going to be kind of a hot topic coming up at VMworld.
This was first published in July 2013