One of the biggest IT costs for a small and midsize business is shared storage, like a NAS or a SAN. Even the most entry-level of SAN’s can cost $10K and up to purchase, plus usually another couple thousand dollars to get it deployed and learn how to use it. For a lot of small businesses, that’s their entire yearly IT budget.
The problem is that shared storage is absolutely needed to get the most out of a modern virtualized environment. Key vSphere features like vMotion, High Availability (HA), and Fault Tolerance (FT) all require some sort of shared storage. So what do you do if you don’t have that $10K or more to buy a shared storage device? You get a VMware vSphere Storage Appliance (VSA) instead! The VSA is software that turns your vSphere Hosts’ (servers) internal hard drives into a highly available (99.9%) redundant shared storage device.
With just 5 clicks, your internal hard drives are setup in a RAID array, mirrored across two or three hosts, and are immediately available within vCenter as a shared storage device for you to use to enable all of the advanced functionality within vSphere.
A VSA VM runs on each host in the cluster (up to 3 hosts), acting as the pass-through device to the hard drives on each host. It then sets up a type of NFS mirroring across each host to make sure your data is online and available, even in the event of a host crashing or needing maintenance.
In fact, I just did a quick quote on a major manufacturers website to see the price difference between 3 servers on the VMware VSA HCL and an entry-level 1GB iSCSI storage array from the same vendor.
The servers were configured as follows:
Dual Intel Xeon E5620
6x1TB SATA HDD’s
The SAN was configured as follows:
Dual Storage Controllers
18x1TB SATA HDD’s
The servers, with a total of 18TB of raw storage plus enough horsepower to run a fairly large SMB’s entire virtualization setup cost $17,037 (without software), while the SAN alone was $19,476. The difference here being that once you add the VMware vSphere + VSA software to the servers, you’re ready to go. With the SAN, you still need to purchase servers to run the VMware vSphere software. Quite a savings, right?
Now, the VSA is not a replacement for all SAN/NAS devices, as it does not have a lot of the features those $10K storage devices do, like replication, snapshots, or clones. It also is limited to the expandability of your hosts for hard drive space and speed. Most modern shared storage devices can go to 100 disks or more – that’s not likely to fit within 3 servers. Nonetheless, if you need access to an inexpensive, redundant, set of storage for your smaller VMware environment, the VSA can definitely be the way to go.
What solution do you have in place for shared storage today? How do you see using VSA in your environment? If you’re using VSA already we’d love to hear from you too! Feel free to leave a comment with any questions you may have.
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