Storage system vendors have developed features and entire arrays designed to help solve these problems, but third-party virtual desktop software tools can also help solve problems for organizations planning and implementing a VDI.
Software products designed to boost storage performance or reduce capacity requirements for VDI projects are available in the areas of storage optimization, predeployment analytics, virtual file systems and application management software.
A VDI implementation increases the number of input/output operations per second (IOPS) that your storage system must deliver, often putting a strain on storage arrays. One approach to solving the VDI IOPS problem is by intercepting many virtual desktop storage requests before they hit the storage system. Atlantis Computing’s ILIO software processes VDI I/O traffic at the Windows NTFS protocol layer and offloads it before it hits the storage, significantly reducing the number of requests that pass through to the array.
“A lot of that traffic [between a desktop and the storage system] has nothing to do with actually storing or retrieving data,” said Bernard Haruindeguy, CEO of Atlantis Computing. “It has everything to do with the Windows OS checking [storage resources]. By processing all that traffic that usually goes to storage, we typically cut 90% of that traffic. Only 10% of it actually goes to the storage, and the rest is processed within the rack.”
ILIO also uses inline deduplication of Windows image components of VDI images to further reduce the amount of data the storage system must process.
And ILIO eliminates the VDI I/O blender effect that occurs when each virtual desktop sends small blocks of random I/O to storage. ILIO converts the small random blocks into larger blocks of sequential I/O to improve system performance.
Other virtual desktop software products help prepare for a VDI implementation by collecting data on how storage, application, network, CPU and memory resources are used.
According to Mark Bowker, a senior analyst with the Enterprise Strategy Group (ESG) Inc., these predeployment analytic tools are nonintrusive agents that install on PCs and laptops. They serve three purposes. First, they help determine which users, computers, applications and servers are best suited for inclusion in a VDI. Second, they can help determine the unique resources and desktop images different groups within a company, such as the graphics arts or accounting department, will require. Third, they can gather data about an entire organization’s storage, network and application use to help properly design and size the VDI. “You can determine what’s actually in your environment, what workloads make sense and how … you move them over [to virtual desktops],” Bowker said.
Citrix Systems Inc. recently acquired App-DNA, a provider of application management and migration, to add functionality to the company’s XenDesktop virtual desktop product. App-DNA AppTitude automates application management and compatibility tasks. AppTitude for XenApp and AppTitude for App-V, respectively, help determine which applications can be virtualized with Citrix’s XenApp and Microsoft’s Application Virtualization systems and how to resolve issues with those that can’t.
Liquid Labs Inc. sells software used by professional IT services organizations such as Dell Services and GlassHouse Technologies, a provider of data center infrastructure consulting services. Liquid Labs’ Stratusphere FIT assessment tools monitor and log individual desktop and user metrics to help determine which users, computers and IT resources are ready for inclusion in a VDI deployment.
Liquid Labs’ VDI FIT analyzer provides insight into an organization’s overall use of storage, network, CPU and memory resources. VDI FIT’s reports can help prevent design problems -- such as not planning for enough IOPS or capacity in a storage system -- that otherwise might sabotage an implementation.
Lakeside Software provides data collection and reporting similar to Liquid Labs but also adds management capabilities. SysTrack Virtual Machine Planner (VMP) is similar to Liquid Labs’ Stratusphere FIT and VDI Fit in that it collects and analyzes system and user metrics and helps identify virtualization-ready servers and desktops. VMP also offers migration planning, as well as storage throughput and space planning.
Virtual clustered file systems
Virtual file systems decouple virtual environments from physical storage resources to provide virtual desktops and virtual servers more efficient access to shared storage systems. Sanbolic Inc. is one of the early players in this market, and more tools are likely to be developed if the number of large VDI deployments increases.
Sanbolic Melio VDI is host-based data management software that supports Citrix’s XenDesktop VDI, Microsoft Hyper-V and VMware vSphere server virtualization platforms. The Melio VDI platform includes several applications.
Melio FS is a symmetrical cluster file system that allows multiple physical servers simultaneous access to individual volumes. The goal is to provide simplified data management for desktop images, optional write cache files, high availability and data protection via Microsoft’s Volume Shadow Copy Service (VSS)-based snapshots of shared volumes.
Melio’s LaScala host-based volume manager software includes transaction management, clustering and locking technologies to allow multiple hosts to access storage volumes. The software also allows storage volumes to span multiple controllers. It supports Windows’ Active Directory and Distributed File System (DFS), failover clustering, and network load balancing.
The Melio platform also includes its Simple Information Lifecycle Manager (SILM) storage management and volume migration software, AppCluster for managing SQL Server clusters and FileScaler for managing Windows’ file service data cluster scaling.
Virsto Software is another player offering a virtual file system, with a focus on storage performance. The company’s Virsto One software sits on the hypervisor host and intercepts random storage I/O and creates a sequential log similar to enterprise databases logs. It then moves the data to disk sequentially for better storage system performance. Virsto offers VDI editions for Microsoft Hyper-V and VMware vSphere.
To provide fast and efficient storage resources in VDI environments, you must separate applications from the underlying desktop image. Storing individual user profiles, each with the user’s applications, would cause your storage capacity and IOPS requirements to skyrocket. Application-layering products separate applications from the underlying OS and encapsulate them so users can incorporate them without bloating the base desktop image.
Liquid Labs ProfileUnity FlexApp allows users to install their own applications into their virtual desktops at login. Using a simple layering architecture, the company says applications can be installed in seconds and follow the profile after the user logs off. Liquid Labs plans to offer ProfileUnity FlexApp for general availability this quarter.
Unidesk Corp. bills its Unidesk Desktop Management software as a virtual desktop management solution. It layers applications into VDI environments, manages desktop images and provides persona or profile management capabilities.
The Ohio Department of Developmental Disabilities (DoDD) runs Unidesk along with Whiptail solid-state drive SAN arrays for its 1,200-user VDI deployment. “What that does is allows us to layer in different software for different people,” said Brian Brothers, DoDD’s network administrator manager, of Unidesk. The product also manages his application licenses so he doesn’t worry about violating those agreements and offers deduplication to save more storage capacity.