Oddly enough, a decent portion of IT professionals still have not experienced SSD. The basic idea is this: with a standard hard drive, there are spinning disks and a mechanical arms that cut down on how many input/output operations per second you get (IOPS) and how quickly you can randomly get a piece of data (latency). With an SSD, there are no moving parts. No home lab or virtualization solution will be complete without SSD.
Edit: This was written as an addendum to a post on building a white box for a home lab. I doubt anyone making storage decisions for their organization would mistake this for advice in a production environment, where you would base your storage solutions on workload, budget, and other factors. That being said, any production virtualization workload these days should probably have SSD involved, either in a tiering solution or pure (expensive) flash storage for critical workloads with high IOPS requirements.
SSD or Spinning Disks?
So! You have a fancy 15k RPM hard drive or two lying around and don’t need SSD? Your state of the art hard drive likely gets on the order of 200 IOPS. Most consumer level SSDs will give you on the order of thousands or tens of thousands of IOPS. Unless your goal is redundancy, a single SSD will beat out most arrays of high performance spinning disks you might build at home.
Why does this matter? If you want to run multiple virtual machines with their own virtual hard disks and data stored in various locations on spinning disks, you will be severely limited by the mechanical pieces of a standard hard drive. You will find this in the enterprise as well. Ask anyone wearing the virtualization hat what their primary bottleneck is, and you will more than likely hear storage IO (RAM otherwise). If you plan to run VMs, nothing should be prioritized over an SSD. RAM would come a close second.
Don’t believe the FUD spread about SSD potentially dying early due to limited writes. This is true, in that you can hit a brick wall. When you hit that brick wall is another matter. Your SSD will keep track of which bits it has written and how often, and spread the load appropriately. I won’t go into the math, but it is safe to say your SSD will most likely last far longer than a standard hard drive.
Lastly, do be cautious before buying an SSD. Once you experience SSD performance, you will likely be motivated to upgrade any laptop(s) or desktop(s) you regularly use. There is no going back. My desktop boots in less than 20 seconds and is noticeably faster than any setup I’ve used in the past.
Picking an SSD
So! You decided to buy an SSD. Which do you pick? Any SSD is an upgrade over a hard drive. The difference between the SSDs you might chose is much smaller. That said, I prefer drives known for a combination of performance, reliability, and nerd-affinity. Go with a Samsung 830 or Crucial M4 and you will be happy. 256 GB seems to be a good price/capacity range and should hold a good number of VMs. I personally went with two. AnandTech and ArsTechnica should provide you with further details if needed. slickdeals (popular or trending deal links) and fatwallet will help you find sales, which are very common.
You can keep your old hard drives
Do keep in mind that you may want to augment your storage with spinning disks. SSDs come at the cost of capacity and price. You may want to keep one or more spinning disks to house large files that don’t need high IOPS, and to house your backups.