Managing storage for virtual environments: A complete guide
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Third-party monitoring tools provide a single interface from which an IT shop can monitor the performance of the storage and servers associated with a virtual environment based on VMware Inc.'s hypervisor.
Some VMware monitoring tools can provide insight into network traffic and drill down into the guest operating systems and the applications as well as supply detailed statistics on the storage to help companies address problems with their virtual infrastructure, according to David Davis, author of TrainSignal Inc.'s vSphere video-training library, a VMware vExpert and VMware Certified Advanced Professional.
In the following podcast interview with Senior Writer Carol Sliwa, Davis discusses the advantages and disadvantages of third-party storage performance monitoring tools for VMware environments and offers up advice for selecting the optimal tools.
What types of tools are available to help IT shops monitor the performance of the storage they use with their VMware server environments?
David Davis: In today's data centers, when you implement a virtual infrastructure using VMware, you're going to have a storage array, a SAN or a NAS, physical servers, of course VMware vSphere, and then the VMware portion is monitored by vCenter. When it comes to the storage, your storage vendor is going to provide you with some sort of storage [performance monitoring] tool. The limitations of those tools that you have by default, once you implement the virtual infrastructure, of course, is that they're tailored towards monitoring just that one thing. So, your storage tool is just going to monitor the storage, but it really doesn't have the insight into the virtual infrastructure. And then VMware vCenter has basic storage monitoring information and insight into the virtual infrastructure, but the reporting and the knowledge that it offers is very limited.
How do the storage performance monitoring tools from third parties distinguish themselves from the traditional monitoring tools from an IT shop's storage vendor or VMware?
Davis: VMware released their own performance monitoring tool called VMware vCenter Operations, and this has further justified why you need third-party or extra performance and monitoring tools in the first place. You've got these storage performance monitoring tools from your SAN vendor, and of course, they only manage and monitor the performance of the SAN. Then you've got VMware vCenter, which can monitor and manage the performance of the vSphere virtual infrastructure, and it also offers some storage statistics. Then there are third-party tools, or additional tools not made by VMware, and these tools really distinguish themselves by giving you the single pane of glass, or the complete package, where you can go to a single interface and not only see performance information about the virtual infrastructure but also information about the storage area network and then tie it all together so that you can see which virtual machines are on what VMware data store and then what SAN LUN that data store is stored on and what SAN it's running on and what the performance of the SAN is. In other words, they're able to tie all these things together along with best-practices information about the virtual infrastructure, things like thresholds, that you might not know just on your own. These third-party performance tools have come up with, over time, recommendations to help you make the most out of your virtual infrastructure.
What are the main advantages of going with a third-party tool to monitor the storage performance with a VMware server environment?
Davis: Again, that single pane of glass is very beneficial, but also [some of these tools] can talk directly to the storage, using something like SMI-S [Storage Management Initiative Specification] to get additional storage statistics. Other tools have great insight into the virtual network, where they can actually analyze what type of traffic is traversing the virtual network and what virtual machine is talking to other virtual machines. Other tools can talk down or drill down into the guest operating systems and even the applications to understand what applications are running and how those applications are performing and even understand what virtual machines are using a three-tiered, client/server application -- who's talking to who and how are the virtual machines related; what hosts are they running on -- and then eventually, what storage they're running on, and how is the performance of all those things related to help you to solve the problems in your virtual infrastructure and analyze the performance of all the pieces of the virtual infrastructure over time.
What are the downsides of using a third-party [VMware monitoring tool for storage performance]?
Davis: Like I said earlier, when you purchase your storage, you've got a tool there. When you purchase VMware vSphere and vCenter, you've got a tool there. So, the first downside would be the additional cost of purchasing a third-party tool. But, to me, even VMware with their recent release of their own performance tool [justifies] that you do need your own performance tool to monitor a virtual infrastructure. So I think that … everyone has agreed over time that [the additional cost is] well worth it. You want to make sure that the tool that you find is best suited for your needs. Of course, I mentioned how certain tools have insight into different things -- the network or the applications. And your tool may not go as deep as the tool from your storage vendor or as the VMware-specific tools do in certain areas. For example, if you wanted to go and modify or analyze the multi-pathing that a host takes to access a storage array through the Fibre Channel fabric, these third-party tools probably aren't going to go into that. So you'd still need to use your vendor's tools to do something like that. Or they might not analyze or allow you to modify the queue depth on a host bus adapter. And so, there are some very deep and very detailed areas that a third-party tool probably isn't going to go into.
What are the top three pieces of advice you would offer to VMware users on storage performance monitoring?
Davis: The first one would be: Make sure you take into account that virtualization is all about increasing the utilization of your physical servers and increasing the utilization of your storage area network. So while you're trying to increase those utilizations to get the most out of your return on investment, you also want to make sure that you don't overutilize those resources and end up in slow application performance and even potentially downtime for end users. So, make sure that you have some kind of performance tool that can show you everything that's going on in the virtual infrastructure, including the servers and the storage, to help make sure that you get the most out of what you're doing without overutilizing it. Also, make sure that your tool can take into account the advanced features of virtualization -- things like thin provisioning, Storage I/O Control, Storage VMotion and so on. Third, make sure that you have a smart tool. You don't just want a tool that has some pretty charts and graphs. You want to make sure you have a tool that really knows the best practices of a VMware virtual infrastructure and can help make recommendations to ensure that you get the most out of your virtual infrastructure.