Virtual Desktop infrastructure, or VDI, for those that don’t know, is essentially a desktop environment hosted on a remote server and/or blade PCs, accessed by users over a network through remote display protocol. For users, this allows them to access their desktop from any location and on any device. For IT administrators, what this means is this – a more centralized and efficient client environment that can be easier maintained and that allows a quicker response to the changing needs of the user and business. Larger organizations have turned to VDI in the past decade as an alternative to the server-based computing model used by Citrix and Microsoft Terminal Services. With your organization, if you’ve decided that VDI is for you, one is then brought to that uneasy thought of how to implement and deploy your VDI.
When you’re ready to take the plunge, one must begin by planning for the storage needs of a new VDI. Your VDI plans should include the adherence to demands placed upon storage with the workload profile of a VDI environment. When moving to VDI, it will introduce the possibility of increased latency and contention for disk resources, should one not pay attention to the demands of their storage. Needless to say, this is EXTREMELY important to your VDI plans.
The understanding of I/0 is key to any VDI plans. Most VDI deployments will display similar I/0 characteristics. Due to the nature of desktop workloads, expect a relatively high writes-to-reads ratio – anywhere between 30% to 40% of reads and 60% to 70% of reads. When planning your VDI deployment, if you’re unsure of your I/0 requirements, a figure of 7 to 10 IOPS per user is a fair guess. While read/write distribution with VDI environments may be different from a traditional server virtualization environment, write activity is comparatively predictable. With read activity however, a smaller amount is subject to huge spikes during boots and log-ons that, if not planned for in advance, can cause major problems. Beware of disk partition alignment – possible partition misalignment may cause unnecessary and costly I/Os to the performance on the back end of shared disk arrays.
Your VDI plans should include getting to know the different disk requirements needed for the different components of your VDI solution. User profiles and home directories can sit on SATA drives without issue. Where applications should reside is entirely dependent on their particular I/O profiles. Now deploying the operating system images of a VDI environment on a SATA drive is a risk, but if it’s the only drive technology available, always supplement it with a significant amount of cache and most important, a large read cache. This kind of foresight should be an integral part to your VDI plans.
Data deduplication is important to VDI storage implementations as well. Most VDI deployments will deploy a large number of Windows C drive images. Block-based deduplication technologies commonly yield space savings up to 80% to 90%. This should be considered for this scenario here in your VDI plans. Post-process block-based deduplication also makes for an excellent fit as there’s not a huge amount of change data being ingest, meaning that space requirements will not explode during the working day.
Next in your VDI plans is to choose a protocol for VDI. The majority of IT organizations choose to deploy VDI on NFS rather than Fibre Channel. NFS over a dedicated 10 Gbps Ethernet is common in larger deployments, as are dedicated VLANs. Fibre Channel is not necessary.
Another thing to consider in your VDI plans – the vast majority of non-VDI desktop machines are not backed up, meaning that if the user’s laptop or desktop breaks, all applications are normally reinstalled. It’s not uncommon for VDI desktops not to be backed up but all the same, many companies will back up their VDI desktops occasionally. It’s not entirely necessary but some prefer it. Also, most VDI deployments are virtualized Microsoft Windows desktops. Make sure that it is in your VDI plans to turn off ALL unnecessary services such as disk defragmentation, partitioning, and virus scanning are turned off.
There are many different aspects to deploying a VDI environment and it is important that all aspects are looked over with a fine-toothed comb beforehand in your VDI plans. A detailed VDI plan will serve you not only when initially implementing it into your IT environment but also, in the future, as IT issues come up.