Storage trends move in time with the evolving needs of organisations. From the first data centers of the ‘60s, whose mainframes needed their own rooms, to the much smaller servers of the ‘80s that morphed into giant server farms, technology has raced to meet the pace of changing data quantities and speeds.
As mobile, BYOD and the IoT began generating massive amounts of data at an unprecedented pace, the race was on again to find efficient and cost-effective storage solutions. VMware’s virtual SAN launch almost three years ago was yet another link in the evolutionary chain, enabling users to use storage within ESXi servers without the need for external storage.
Companies looking to scale out virtual storage were excited by the prospect of vSAN to deliver fast, resilient scale-out storage. Server admins were looking forward to using vSAN because it gave them a symmetrical architecture that did not require external storage, thus being able to use storage within existing servers. It also doesn’t require specialised storage skills.
Creating a flexible, scalable architecture
However, no one solution can do everything, and as enterprises began to deploy vSAN across their environments, they noticed something significant was missing.
The problem was that, despite its many benefits, vSAN lacks support for a file system. The importance of having a file system within a data center cannot be overstated. Without a file system, the guest VMs cannot share files between them, and are forced to use an external NAS solution as shared storage. Without a file system overlaying this data, it becomes impossible to scale efficiently.
This problem must be overcome, but there is another that also must be addressed. With the explosion of virtual environments across every industry, an enterprise setting requires support for hypervisors as well. Therefore, a scale-out vNAS needs to be able to run as a hyper-converged set-up. As a result, a software-defined infrastructure strategy makes sense here.
Because virtual network-attached storage does not use external storage systems, the vNAS must be able to run as a virtual machine and make use of the hypervisor host’s physical resources. The guest virtual machine’s (VM) own images and data will be stored in the virtual file system that the vNAS provides. The guest VMs can use this file system to share files between them, making it perfect for VDI environments as well.
This creates an architecture that allows users to start small and scale up. It’s a set-up that is flexible and scalable because it is software-defined, supports hardware that is both fast and energy-efficient, and supports bare-metal as well as virtual environments.
We’re not done yet, though; protocols must be factored in. vSAN uses a block protocol within the cluster, but when designing storage architecture, it is important to support many protocols. Why? In a virtual environment, there are many different applications running, having different protocol needs. By supporting many protocols, the architecture is kept flat, with the ability to share data between applications that speak different protocols, to some extent.
Putting it all together
Each of an enterprise’s sites has its own independent file system. It is probable that different offices have a need for both a private area and an area that they share with other branches. So only parts of the file system will be shared with others. This common scenario, so essential to the functioning of a typical business, cannot be achieved with a vSAN.
Enterprises are increasingly using a hybrid cloud, storing data both onsite and in the cloud. Being able to use just the amount of cloud storage required, depending on the group’s needs, delivers excellent gains in performance and flexibility. The challenge is that in vSAN, there is no file system that can be extended to cover the data in the cloud, and files cannot be shared between the onsite location and the cloud.
With the vNAS-based hybrid cloud architecture detailed above, though, each site has its own independent file system. In a typical organisation, different offices will need both a private area and an area that they share with other branches. As a result, only parts of the file system will be shared with others.
Enterprises can allocate a certain portion of a file system for others to mount at any given point in the other file systems, which delivers the flexibility needed to scale the file system beyond the office walls – ensuring that the synchronisation is made at the file system level in order to have a consistent view of the file system across sites. Being able to specify different file encodings at different sites is useful, for example, if one site is used as a backup target.
A forward-looking storage partnership
In a storage landscape in which data swarms in by the petabytes every day and most data centers are still using vertical scaling solutions for storage, enterprises need alternatives – and fast. They need to scale quickly and cost-effectively to stay in business. vSAN provides the speed enterprises need, along with an easy set-up, but it requires a partner to be maximally useful for the enterprise. The similarly named vNAS provides that partnership with its ability to span all servers with a single file system. This combined approach will give enterprises the flexibility and scalability they need to move into an ever-expanding data universe.
Stefan Bernbo, founder and CEO, Compuverde
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