While the original case for replacing individual desktops with a virtual desktop infrastructure (VDI) was based on hardware cost savings, sinking desktop prices combined with the high cost of quality data centre back-end infrastructure have generally killed that as a rationale for VDI. However, emerging concerns over security, bring-your-own-device (BYOD) management, mobility, etc. have become the new driving force for adoption of VDI technology.
Given that purchasing new infrastructure for a largescale VDI implementation can represent a prohibitive upfront capital cost for many SMB firms, many are looking for alternatives to the traditional approach. While fairly powerful x86 servers with enough CPU and memory are relatively affordable, new networking and storage infrastructure can be the cost driver of a new implementation. Both networking and storage are critical to a VDI implementation, as network and storage I/O bandwidth can often be the bottleneck in a VDI environment.
While upfront infrastructure costs are a valid concern for SMBs, most companies have existing networks with low latency and enough bandwidth to handle new VDI loads. If that is not the case, there are new technologies available such as 100Gb Ethernet (100GbE) that can be strategically implemented to boost network bandwidth without breaking the bank.
More often, storage I/O is the limiting factor for VDI performance. The traditional answer to that problem has been use of a SAN with Solid State Drives (SSD) as the shared storage behind a VDI environment. This is where the person holding the SMB budget often starts to push back.
A high-end SAN with SSD to boost storage I/O per second (IOPS) can easily run at US$300,000 1 or more as an initial capital cost. A typical SAN may have a 16Gb Fibre Channel (FC) Host Bus Adapter (HBA) that can also require expensive upgrades to increase throughput depending on the size and number of storage spindles attached.
1 Approximately $371,499.00 SGD (based on a $1.24 exchange rate as of April 10, 2013)
A SAN with SSD comes pre-configured to share and move data and files, incorporates high availability features, and is designed to manage task allocation between SSD and disk. However, all of this comes at a high cost. If that cost is too high for many SMB customers, an alternate approach has become more feasible.
This alternate approach uses new storage management technology available in hypervisors (e.g., Microsoft Hyper-V SMB 3.0 file shares and VMware VMotion in vSphere 5.1) that enables many critical advanced features like VM mobility and remote clustering without shared storage.
This means companies can leverage local storage, running a RAID configuration, instead of a SAN for their virtual environment.
Using direct attached storage has two key financial advantages:
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