In this SearchStorage.com expert Q&A, Greg Schulz, founder and senior analyst at The StorageIO Group, discusses how to manage data with virtual servers. Find out what to consider when looking at data management tools for virtual servers, what storage vendors are doing to support virtualized server environments, what features to look out for when trying to simplify management for virtual servers, and whether or not you should invest in SRM tools. To hear the entire interview, listen to the MP3 below.
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Managing data in a virtualized server environment
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SearchStorage.com: What's the most important thing to consider when looking at data storage management tools for a virtualized server environment?
Schulz: First and fundamentally, keep in mind that virtual servers are stored on disk as a file. While that may seem rather elementary for some, it's an important notion because what that means is that managing virtual servers is in many ways like managing other data. It's important to make sure that virtual servers are backed up, protected and secured. But there are some things that need to be considered differently with virtual servers. Many of the same tools that you may already use for managing your storage, data, or your physical servers will be the same for your managing your virtual servers; it might require you to make moderate upgrades or add a plug-in. At the same time, there are also other tools that are optimized for working in those virtualized server environments.
SearchStorage.com: How are storage vendors doing when it comes to support for virtual servers?
Schulz: It's all over the board. If you show me a vendor that doesn't have the word virtual in their product lineup, their literature, or their buzzword lingo discussion, then I would say that's unique. However, vendors are doing a variety of things. Some are very aggressive in terms of integration, whether that may be with VMware vSphere's Site Recovery Manager (SRM), Microsoft Hyper-V, Live Migration, Citrix or Xen. Some vendors are much further along than others; some are on basic operability; and some are tested and certified. Some vendors are even more tightly integrated, such as the VMware VAAI API initiative. So all over the board it's safe to say that all of these vendors are at least virtualization aware and that they can work in a virtualized server environment.
Once you determine whether or not a vendor can work in a virtual server environment, the rest comes down to other features such as their actual tested, certified, and supported level of integration that they have. Also, you'll want to understand the capabilities that they have or are enabled.
SearchStorage.com: Do virtual servers need virtual storage?
Schulz: There's a common myth that if you have a virtual server, you must have to have virtual storage. Then because of that, you'll need a virtual data center and a virtual network. That's not true; virtual servers do not need virtual storage. However, they may complement each other and work together in some cases depending on the particular product, solution or technology.
What virtual servers do need in terms of storage is something fundamental, and that is shared storage. Unless you're going to go to an environment where all of the virtual servers are going to physically sit on a single server, then you could get away with having dedicated internal non-shared storage. But in most every other environment you're going to have two or more servers that need a common denominator -- shared storage. And that shared storage could be in the form of shared external SAS, shared external iSCSI, Fibre Channel (FC), Fibre Channel over Ethernet (FCoE) or network-attached storage (NAS).
SearchStorage.com: If I want a storage solution that will simplify management for virtual servers, what are some items I should have on my shopping list?
Schulz: There is a basic checklist for storage solutions. These include basic scalability, performance, availability and resiliency. In terms of no single points of failure, these include basic redundancy, hot swap components, different RAID levels for tuning, and snapshots.
There are other features and questions you should look out for in terms of virtual servers. For example, how does the storage solution plug into VMware SRM? In terms of being able to support snapshots and replications, how does it work with SRM? Does it have a plug-in or an agent that makes that integration more seamless? How does it work in the VM world with VCB? How does it work in a Microsoft environment with Microsoft Hyper-V or Microsoft management tools? Are the vendor's storage solutions straightforward or do you have to go to that vendor's particular toolset and do some of the configuration from there? Or can you go to a VMware vConsole and do all the provisioning, setup and allocation of both the storage and the virtual system all from one interface?
So overall, look for the basics and the fundamental capabilities that you would look for in any storage product, but then ask yourself how that solution plugs in and works with in a seamless integrated type manner with different toolsets, in particular toolsets you might already have.
SearchStorage.com: If I have virtualized server environment, and I want to simplify management, does that mean I am going to have to invest in SRM tools? If not, what are my other options? If so, where do I start? Should I go with a third party, or with my own storage vendor?
Schulz: SRM, to many storage professionals, means storage resource management tools. These SRM tools determine your storage utilization and capacity to utilization. And many of those tools have now been enhanced to also report on performance and activity. Some even report on response time, energy usage and availability. However, from the virtual server standpoint, specifically in the VMware community, SRM means Site Recovery manager. In other words, it's the framework within VMware for managing business continuity (BC) and disaster recovery (DR), managing your snapshots, your replication and your failover environment.
So does an environment need SRM tools? Well it depends. If you're using VMware and if you're going to be doing BC/DR, you need Site Recovery Manager tools, plugins or interfaces for managing that aspect. On the other hand, resource managing tools, whether they are system resource or storage resource management tools, also become important for giving you information of what you have, how it's being used and how it's being allocated. In other words, if you're in a virtual server and you're consolidating, you need to know how busy a particular server is, how much disk I/O it's doing, and what are its performance characteristics both in terms of IOPs, MBps and response time. This is in addition to its capacity so that you can avoid oversubscribing or causing congestion. Keep in mind that aggregation can cause aggravation unless you have a situation awareness of how those resources are doing. That might mean using an existing operating system, vendor tools, or additional third party tools, but it also might mean looking at new tools that provide you end-to-end cross technology to give you that system resource and that analytics capability.
This was first published in September 2010