Atlantis Computing today released its ILIO Diskless VDI product, which uses RAM instead of disk drives to boot...
up images in nonpersistent Citrix or VMware VDI deployments. Using RAM speeds performance and can reduce the amount of dedicated VDI storage required.
Atlantis Computing claims that using memory in place of disk drives reduces the boot time for a virtual desktop to 12 seconds, compared with the typical one-minute or so boot time for physical desktops.
“We make the virtual desktop image so small that it can run on the local server memory, so the benefits are twofold,” said Seth Knox, Atlantis Computing’s director of marketing. “First, there is no storage to maintain so you are eliminating the operational and capital expenditures. This translates into a cost of $200 per desktop. That was not possible to do before. Second, it’s much faster. You can get 36 times more IOPs per desktop.”
Atlantis’ ILIO virtual desktop software runs on top of a hypervisor. While the vendor claims it is compatible with Hewlett-Packard Co., Dell Inc. and IBM servers, Altantis recommends using Cisco Systems Inc.’s UCS B230 M2 blade servers because of Cisco’s Extended Memory Technology. Cisco’s UCS has more memory slots per server and per processor than other servers. One Cisco chassis holds eight individual blade servers, enabling as many as 160 virtual desktops per blade, and one rack holds as many as five chassis and 6,400 virtual desktops.
“A customer would use the same amount of memory for Atlantis ILIO Diskless VDI with Dell or HP servers as you do with Cisco,” Knox said. “The difference is that Cisco UCS servers tend to have more memory slots per server and per processor.”
Knox claimed that when ILIO is used with a Cisco UCS B230 M2 blade, the hypervisor uses 2 GB of RAM in one blade server and the ILIO software uses 6 GB of RAM and one CPU. One hundred and sixty virtual desktops can use up to 320 GB of RAM.
Substituting RAM for hard disk drives tackles the biggest drawback in virtual desktop deployments, analysts said.
“The storage performance is really the bottleneck in any VDI deployment, and if you load up hundreds of virtual desktops, the performance is horrendous,” said James Bagley, senior analyst for Storage Strategies Now. “Any drive, on a good day, won’t do better than 200 IOPS. Atlantis can get more than 300 IOPS per user. There are a number of vendors working on this, but it is the first time I’ve seen it work on UCS blades to produce this kind of performance.”
Is it really diskless?
The 451 Group’s senior analyst for storage and systems, Henry Baltazar, said Atlantis’ diskless claim is misleading because it is diskless only for nonpersistent data. Nonpersistent virtual desktops don’t keep user data or settings because they refresh whenever they start up or shut down. Persistent desktops maintain user data and settings.
With a persistent desktop, the user connects to the same virtual machine (VM) every time. The user is given a random VM from a pool when a nonpersistent desktop is used. When using RAM for nonpersistent virtual desktops, data created needs to be stored in an array or NAS filer because the desktop is stateless and is wiped clean each time it is rebooted.
“When you say ‘diskless VDI,’ it’s not really diskless,” Baltazar said. “They are marketing this for nonpersistent desktops, and when you create data, it has to reside in another repository. The application and operating system is diskless, but it’s not diskless for the user-created data. It will have to be stored on a NAS or SAN.”
Paetec Communications, a Fairport, N.Y., telecom service provider owned by Windstream, is using ILIO Diskless VDI with Cisco B230 M2 blades for a proof of concept for a nonpersistent VDI deployment for its developers and sales applications. Steven Bell, Paetec infrastructure systems architect, said his company purchased eight Cisco servers configured for 512 GB of RAM. Paetec runs Citrix XenDesktop and XenApp for VDI.
“So far we have about 100 virtual desktops, and we are using 35 GB of RAM,” Bell said. “We want to see how well we will be able to shrink our developers’ storage utilization. If this works out, the plan is to move everything to Atlantis.”
Bell said Paetec uses a NAS device to store content for its virtual desktops.