The release of VMware Virtual SAN (VSAN) has generated a lot of buzz with much discussion on how it can be used to replace traditional storage arrays, create converged storage infrastructures within data center environments and how large it can scale up to. However, no one is questioning the suitability of VSAN outside the data center.
The arrival of VSAN also marks the end of VMware vSphere Storage Appliance (VSA), which had been positioned as their Remote Office/Branch Office (ROBO) storage solution. VMware has withdrawn the availability of VSA as of April 1, 2014, providing existing VSA customers with only a few weeks notice. With the hasty retirement of their ROBO solution, VSA and with VSAN focusing on the large data center deployments, what storage options are available for edge enterprises running VMware? Customers that have tens or thousands of edge sites require a storage solution that can deliver high availability with a minimal IT footprint at a low cost. Does VSAN really fit the bill? Let’s take a look at the requirements and costs of VSAN.
VSAN Server Requirements
Typically, customers with edge locations strive to keep the server and storage infrastructure to a minimum, preferring to only deploy 2 servers and a small amount of shared storage to maintain high availability. VSAN has a minimum requirement of three servers, adding an extra 50% to the cost of the solution.
VSAN Storage Requirements
Each server in a VSAN cluster must have at least one solid-state disk (SSD) and one hard disk. While the performance offered by SSDs may be required for some applications, the majority of enterprise edge applications simply do not require them. This “hard” requirement increases the cost of the infrastructure at each edge location, even though the performance may not be required.
VSAN Memory Requirements
VSAN has the following memory requirements; a minimum of 6GB for a single disk group, up to 32GB for the maximum of 5 disk groups.
VSAN Networking Requirements
VSAN requires, at a minimum, a private 1Gb/s network to connect the servers, ideally two or more to provide resilient connectivity between servers. However, as per the vSphere 5.5 documentation, best practice would be to use a 10Gb/s network. While it is not mandatory 10Gb/s networking is rarely required or even available at enterprise edge locations. This would again increase the infrastructure costs.
VSAN Hypervisor Requirements
Reading through the VMware ESXi 5.5 Update 1 release notes it is clear that VSAN is implemented as a VMware vSphere kernel module only available in VMware ESXi 5.5 Update 1 or later and must be managed by vCenter Server 5.5 Update 1.
As VMware ESXi 5.5 Update 1 and VSAN was only made generally available on March 11th 2014, it maybe considered too new for some enterprise organizations to adopt and deploy. Many may opt to wait until a future release is available and deploy once the initial bugs have been ironed out. In addition to this VMware have made it clear that there is no easy upgrade path from the beta version to the generally available version. In fact the only option is to perform a reinstallation.
Being implemented as a kernel module, VSAN creates hypervisor lock-in, restricting customer choice and eliminating the practice of multi-hypervisor strategies.
In addition to the increased server, SSD and memory costs, VSAN needs to be licensed separately, which is over and above the base vSphere licensing. Current list prices for VSAN are $2,495 per CPU socket. Therefore for 3 hosts with 2 CPUs each, VSAN licensing would add $14,970 to the infrastructure costs.
SvSAN – A Dedicated Solution for the Edge
The introduction of VMware VSAN has validated the need for a software approach to delivering shared storage. VSAN, is however clearly aimed at data center implementations where the higher costs and server requirements can be justified when replacing traditional storage arrays. This focus and VMware’s decision to end the availability of VSA would indicate that VMware are backing away from the edge.
In short VSAN is not an appropriate solution for the enterprise edge; it needs a minimum of 3 servers, each requiring an SSD, more memory and additional VSAN licensing all of which makes it prohibitively expensive, especially as the number of remote sites increases.
A better solution would be to deploy StorMagic SvSAN, which has been specifically designed and optimized for enterprise edge environments that require highly available, shared storage.
SvSAN has several deployment options, starting from the all-important two-server configuration required by the edge, with the ability to scale-out to unlimited nodes. This combined with lightweight server resource requirements, the capability of using internal server storage including SSDs and running on either VMware vSphere or Microsoft Hyper-V, along with flexible capacity based licensing makes SvSAN the perfect solution for enterprise edge environments.
For more information on SvSAN call US +1 800 517 5282, UK +44 (0)117 9527390 or email firstname.lastname@example.org.
To download a free trial visit www.stormagic.com.