One of the concerns raised in our cover article, "Why Your IT Guy Hates the Cloud (and how to fix it)" is performance. Is the server you get in the Cloud going to perform as well, or better, than the server you are using at the office? If performance suffers, the results can be lack of productivity in your employees, frustration from customers, and loss of revenue.

Before we dive in, it’s important to understand a key principle of data storage: IOPS (Input Output operations Per Second). IOPS is a common metric used to measure performance of storage devices. Generally more is better, and systems that support large amounts of IOPS cost more than systems that don’t. There are too many things that can affect IOPS, and we can’t possibly look at them all. However, we will address two things that have the largest impact on your performance in the Cloud: data storage connections and types of disks being used.

First, what is the data storage connection?

This is the connection that your server uses to access the disk (storage device). This connection will have a direct impact on the performance of your server. With Cloud servers, this connection usually goes to a shared disk system located outside of the servers themselves.

Providers will make these connections to the shared storage via multiple mediums with the most common being Ethernet and Fiber Channel. If the connection is Ethernet you should make sure the connection is 10Gbps (Gigabit Per Second). Anything less than this and the type of disk you choose will have little impact on the performance you experience. Fiber Channel or FCOE (Fiber Channel Over Ethernet) can be a good solution also, with 8Gbps being the top speed. The reason 8Gbps is sufficient (versus 10Gbps with Ethernet) is because with FCOE the data is sent in a different way that is more efficient than Ethernet. You should also make sure your data storage connection is separated from the normal traffic on the Cloud server. This will ensure your disk I/O has priority over standard Internet (HTTP) traffic and will add an extra layer of security to your data.

Second, what type of disk is being used?

The second factor to consider is type of disk being used. Currently, there are three basic types of storage: SATA (Serial Advanced Technology Attachment), SAS (Serial Attached SCSI), SSD (Solid State Disk). The right choice is dependent on use and budget.

Each of these storage mediums has positives and negatives. SATA has the lowest overall performance, but also comes with the best price per MB (Megabyte). SAS has a good performance boost over SATA, but has a substantially higher price per MB. And, SSD gives you the highest performance, but is the most expensive per MB.

The general rule is - as performance (IOPS) goes up, price goes up, and price per MB goes up.

So what is the right choice for my application? Well, that’s hard to say. This is something that depends on your application. And, since the price of a SATA disk can be 1/5 the price of a SAS disk and 1/20 the price of a SSD, you’ll want to be sure you’re making the best choice without buying more than you need.

When it comes time to choose storage for your application, you need to ask one final and important question. Will I be stuck with this decision? And the answer should be, no. If you choose a good Cloud service provider, they’ll be able to adjust the quality of storage that your application is running on. If you need more IOPS, you’ll be able to simply dial it up. And if you need less, dial it down. Flexibility is one of the main advantages of the Cloud - you’re not stuck with your decision like when buying a server for your office. In the Cloud, if you don’t like it, you change it. You simply stop paying for the old service, and start paying for the new service.

The best storage choice is usually going to achieve the right cost for performance balance that make sense for your business. Talk with your IT staff or service provider about the options of testing server performance to help you make the best decision.