While it's possible to run VMware vSphere without shared storage, if you want to make use of advanced vSphere features...
such as vMotion, Storage vMotion, High Availability, Distributed Resource Scheduler and fault tolerance, you'll need shared storage.
For a full production deployment of VMware, you'll likely need to invest in a shared storage system that's properly sized to your I/O requirements. In some scenarios, low-cost VMware shared storage makes sense. For instance, perhaps you are going to test advanced vSphere features in a lab environment or verify your configurations before you go into production. Or, maybe you even plan to implement high availability in a small vSphere cluster. In those cases, you can get by with a low-cost shared storage system. Here are the general decision-making factors for low-cost shared storage for VMware:
- Performance: How many IOPS does it provide?
- Scalability: Up to what storage capacity can you obtain?
- Compatibility: Is the storage certified for your version of vSphere?
- Feature set: Does the storage offer disk redundancy, tiering, caching, thin provisioning and so on?
- Connectivity: How many Gigabit Ethernet ports (for iSCSI and NFS) are there?
- Protocols: Does it support iSCSI, NFS, Fibre Channel, SMB, etc.?
All of those factors apply to hardware-based shared storage, and all except performance, scalability and connectivity apply to software-based. That's because those three factors are controlled by the hardware that supports the software-based storage.
Low-cost shared storage: You get what you pay for
If you use shared storage to support your virtual environment, every block of every OS, application and data inside a virtual machine is stored on it. If you want good, production-ready performance in the virtual environment, you'll need to properly size your shared storage based on IOPS requirements. In other words, don't buy the lowest-cost shared storage option and expect it to perform as well as higher-cost storage options.
The good news is that there is no shortage of options for low-cost VMware Inc.'s shared storage. But what exactly is "low cost"? I've set the bar at $5,000 or less for a company lab or small production environment, and I've broken down low-cost shared storage options into two categories: hardware-based storage and software-based storage.
It's likely that hardware-based storage will offer you greater performance (more IOPS) than software-based storage. However, hardware-based storage also costs more, in general, than software-based options.
Low-cost, hardware-based storage for virtualization
With a low-cost storage array, the performance, feature set and scalability are lower than with a more expensive array, which can easily cost $10,000 or more. And the low-cost arrays almost certainly will not include solid-state drives or features such as support for VMware's vStorage APIs for Array Integration (VAAI).
The following are examples of low-cost hardware-based arrays for virtual infrastructures:
- Drobo: Known for their "Beyond RAID" technology, which provides RAID protection without the need for RAID configuration, Drobo Inc.'s arrays are sleek-looking and "stupid simple" to implement. You can use your own disks, no matter their sizes. With its RAID protection, two disks could fail without loss of data. We recommend that you try the company's daily live demo to see the interface for yourself.
- Synology: This company offers a wide range of certified arrays with an easy-to-use user interface. Besides storing VMs, Synology Inc.'s DiskStation Manager product works almost like a Windows OS: You can add applications to it to do some amazing things, such as store iTunes media on it or use it as a WordPress Web server, VPN server or mail server. Synology also offers a live demo of the interface that's worth watching.
- Iomega: Arrays from Iomega Corp. (which is owned by EMC) are popular with vSphere admins for lab environments. While Iomega may not have a user interface as impressive as Synology's and its arrays may not look as cool as Drobo, it has a number of affordable vSphere lab options that you should consider.
Here are VMwareVideos.com. we have had all three of these low-cost storage arrays in our vSphere lab. They all have worked very well for us in performing advanced vSphere features.
Is it 'VMware Ready'?
For a lab environment, admins typically don't worry about the storage having a VMware stamp of approval. But for more important environments, they are concerned because VMware will not support a vSphere installation if it has not approved of the storage. Before buying, look up the device in the VMware Compatibility Guide to find out whether it is supported by VMware, and, if so, check on which models of the hardware and by which versions of ESX.
Low-cost, software-based storage for virtualization
Software-based storage solutions have benefits. At the top of the list is the fact that they tend to cost less than hardware-based because, frankly, it's up to you to provide your own hardware and disks for them to run on. Some software solutions may even be free, though, again you must provide the hardware and disks. And, you don't have to receive shipment and unpack, like you do a physical storage array.
Here are some examples of software-based shared storage solutions that work with vSphere:
- OpenFiler: This is a totally free, open source solution and can be run in a virtual machine (VM) or on a physical server. It supports NFS and iSCSI. And it has a Web-based interface, which can be a bit confusing to configure for the first time.
- StarWind iSCSI SAN: StarWind Software Inc. has a free edition and a commercial edition (with advanced features). It runs on top of the Windows OS to create an iSCSI SAN for storing VMs. Because it works just like any other Windows app, it's fairly easy to configure.
- Nexenta: Available in a free community edition (for non-commercial or education use only) or in editions that scale up to some of the largest software-defined storage networks in the world, Nexenta Systems Inc.'s virtual storage solutions specialize in virtualization.
- VMware's vSphere Storage Appliance: A vSphere 5 addition to the virtual storage appliance market, the vSphere Storage Appliance can only be used to store vSphere virtual machines. It uses local disks on ESXi hosts and requires a minimum of two ESXi hosts to function. It is fully supported by VMware for advanced features but has a number of scalability limitations. VMware's VSA isn't available in a free edition, but you can evaluate it for free for 60 days.
Selecting low-cost, shared storage for a virtual infrastructure
When it comes to choosing between hardware-based and software-based shared storage for vSphere shared storage, there isn't a hard requirement to use one or the other. There are small hardware-based storage solutions that may not support your users, and there are software-based storage systems that would. By the same token, there are software-based solutions that wouldn't give you the throughput you need, but hardware-based solutions that would. The bottom line is that while hardware-based storage is traditional, you can't pick your solution solely based on whether it's hardware or software.
It's most important to consider the decision-making factors described above (cost, performance, scalability, compatibility, features, connectivity and protocols) when making a decision. Don't make any assumptions, because arrays from different companies (and even within the same company) can be very different.
David Davis is the author of the best-selling VMware vSphere video training library from TrainSignal Inc. He has written hundreds of virtualization articles on the Web, is a vExpert, VCP, VCAP-DCA and CCIE #9369 with more than 18 years of enterprise IT experience. His personal website is VMwareVideos.com.