When you buy storage for your ESX or Hyper-V infrastructure, what's more important to you - capacity or performance? Is a GB or an IOPS unit worth more to you?
If you balance the two, what steps to do take to do so? How do you analyze your workloads to determine overall storage impact?
Personally, now that we have an infrastructure in place, I'm finding it easier to model new workloads than it was when we initially got underway. Besides being more experienced, the virtual environment makes it easy to install and test actual workloads on the hardware before moving those workloads into production. So, when we decided to move to Exchange 2010, the IT staff at Westminster had their mailboxes moved to the new virtual Exchange 2010 server so that we could be the test subjects to determine if and where there might be bottlenecks.
Most of the time, its a balancing act between capacity, performance, and cost.
We work with a storage product that uses SAS backplanes, SAS expansion ports, and a FC-based RAID controller. We can then mix/match SAS and SATA drives to obtain the capacity (SATA) and performance (SAS) we need within the environment. The chassis we use has a modular controller system, allowing us to start with a single, dual-port 4GB FC controller, and as budget permits and requirements dictate, we can add a second controller or upgrade to one or two dual-port 8GB FC controllers. A single-controller 4GB Titan enclosure with 3-600G SAS and 9-1000G SATA drives can be had for less than $10,000. Up to 4 expansion shelves can be connected for up to 60 SAS/SATA bays. There are some specific requirements to get optimal performance from SATA, related to placement within the enclosures, but the flexibility and relatively low cost make it attractive to many of our clients.
We work with a lot of mid-sized companies that are just now moving to larger infrastructures and virtual environments. These units help us stay within budget and provide a platform that can migrate to improved reliability and performance without replacing major infrastructure components or migrating data.