By now, it's no secret that a virtual desktop infrastructure (VDI) heavily stresses a storage system. That is especially the case for burgeoning Desktop as a Service provider Whoa.com Chief Information Officer Yunexy Eloy as he builds out a VDI infrastructure that he expects to hit between 25,000 and 50,000 virtual desktops within three years, and maybe eventually grow to 100,000.
Eloy said he realized early on when building the DaaS platform last year that flash storage would be a requirement if Whoa.com customers are to launch their desktops without delay.
"A lot of people make the mistake of not taking storage into consideration when designing VDI," he said. "It is extremely important because user workloads are unpredictable. When you have a lot of user desktops loaded up for boot storms, you will have major issues with spinning disk arrays. They just cannot handle the IOPS required for that. As a service provider, we cannot afford to have a bad user experience. We cannot afford to have any delays when the customer goes to boot up desktops in the morning."
Eloy's first choice was to use its NetApp FAS running Clustered Data OnTap in a hybrid system with Flash Cache cards and spinning disk. Whoa.com uses NetApp as the storage for its IaaS and business applications, but couldn't get the IOPS required for DaaS.
That led Eloy to check out all-flash systems. He looked at arrays from Nimbus Data, Pure Storage and SolidFire before acquiring a Nimbus Gemini array last September. He said he liked the way Gemini scales, its multi-protocol support, deduplication and performance.
Eloy was impressed that Nimbus supports 40 Gigabit Ethernet (GbE), although he is using its four ports per controller for 10 GbE Ethernet now. He is also only using NFS now, but expects to add Fibre Channel eventually to boot from the storage area network.
"The other arrays would consume way too many of our 10 Gb ports, which are expensive," he said. "With Nimbus, we could scale up to 48 TB of raw flash storage within a 2u unit. To accomplish that with other arrays would take quite a lot more of our rack space and consume more power. With Nimbus, we can start small and scale up as needed."
Whoa.com started with 18 TB of solid-state drive (SSD) capacity at its Hollywood data center, with plans to add capacity as it adds DaaS customers. As the customer base grows, Eloy said he plans to put Gemini arrays in Whoa.com's Las Vegas and Virginia data centers.
Whoa.com's VDI is built on the Citrix platform, and its DaaS will offer a fully loaded desktop to customers, including Microsoft Office 365, hosted Exchange mailboxes, Lync for video conferencing and a SharePoint site. Eloy estimated each desktop could generate 165 IOPS, meaning his storage will have to handle millions of IOPS.
In benchmark testing, Eloy said his hybrid NetApp with Flash Cache hit about 60,000 IOPS with about 20 worker servers. The Nimbus Gemini hit about 480,000 IOPS with two worker servers. The worker servers were configured as large virtual machines running Microsoft SQL and Exchange.
Even with those IOPS, a Gemini array probably won't be able to host more than 4,000 virtual desktops, so the ability to scale quickly is important.
"We don't know what the workload is going to be until we have sales completed, but we know [we] will need to scale up," Eloy said. "Our automation platform is designed to scale up to 100,000 desktops. We'll need to scale up our hardware side from our compute, network and storage."
Eloy said deduplication will help get more out of the SSD capacity. So far, he said he is getting about [a] 70% dedupe ratio while running Whoa.com's SQL databases.
"Our dedupe ratio will decrease with our diverse workloads with VDI, but dedupe will still be critical with virtual desktops," he said.