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December 20, 2013

IBM and Atlantis Deliver with Persistent VDI in a Flash – 13x Faster Desktop Performance than a PC and 6x Faster than a MacBook Air

Seth Knox - Atlantis


Since August of 2013, IBM and Atlantis Computing have teamed up to deliver several integrated desktop virtualization solutions for Persistent VDI, Stateless VDI and Citrix XenApp deployments based on the IBM PureFlex, IBM Flex System, and IBM FlashSystem platforms optimized with Atlantis ILIO software. In our initial persistent VDI solution, we highlighted test results of our Persistent VDI In-Memory architecture with IBM v7000 storage for backup and recovery. 

We recently completed additional testing of Atlantis ILIO Persistent VDI with the IBM FlashSystem and the results were phenomenal. Given the performance, density, recovery time and cost of the IBM FlashSystem-based architecture, we recommend that any customer planning a Persistent VDI deployment over 1,000 persistent desktops use the Atlantis ILIO Persistent VDI solution with IBM FlashSystem. Also, if you are an IBM FlashSystem customer already using FlashSystem with mixed workloads, the test results confirm you will not experience any degradation by allocating space on the current array to run persistent virtual desktops.

Why are we recommending the FlashSystem option? The performance is better (6x the disk performance of a MacBook Air), the HA recovery time is better (1 min 14 seconds) and you can support up to 4,000 users with only 1u of storage. Did I also mention that the total cost per desktop is about the same as using Atlantis ILIO In-Memory with the IBM v7000? This cost is about the same because the higher upfront cost of the FlashSystem is offset by lower RAM requirements on the servers (256GB vs. 384GB) and a dramatic reduction in datacenter space, power and cooling.

Solution Overview & Benefits

Before we get to the test results, let’s take a look at the joint solution using IBM PureFlex, IBM Flex System and IBM FlashSystem with Atlantis ILIO software-defined storage for VDI. The integrated solution consistently delivers high desktop performance as projects scale, while reducing storage requirements by up to 95%.  Built on fully validated reference architectures tested at the IBM Innovation Center, this virtual desktop solution provides flexible deployment options that scale to tens of thousands of users.

  • Lower than PC cost – saves hundreds of dollars per desktop as storage capacity and performance requirements are reduced by up to 95% with Atlantis ILIO ® optimization software. In addition, the IBM FlashSystem storage can support thousands of users in a 1u datacenter footprint, dramatically lowering OPEX costs.
  • Better-than-PC user experience – cost-effectively delivers better-than-PC performance including faster boot/login times, near-instant application launches and disk performance that is 6x faster than a MacBook Air.
  • Lower project risks – proven and flexible solutions that scale to tens of thousands of desktops without the risk of storage or network bottlenecks, while enabling high availability and disaster recovery.
  • Management at scale – automated deployment and configuration that reduces mistakes.  Simplified architectures that lower the operational costs and performance risks of deploying persistent VDI.

The IBM FlashSystem and Atlantis ILIO Sample 1,000 Desktop Architecture

The following configuration is designed to support 1,000 persistent virtual desktops with 50GB per desktop of storage (i.e. 50TB of logical storage). The configuration scales to tens of thousands of virtual desktops by adding additional Flex Compute nodes.IBM FlashSystem and Atlantis ILIO Diagram

  • 1 IBM Flex System Enterprise Chassis with IBM Flex System Manager
  • 11 IBM Flex Compute Nodes 2 x Intel Xeon processors (E5-2600s) and 256GB of RAM
  • 8 Flex Compute Nodes running virtual desktops with 125 users per server
  • 2 Flex Compute Nodes as infrastructure servers configured with HA
  • 1 spare Flex Compute Node for fail-over
  • 1 10TB IBM FlashSystem 810 (1U) for virtual desktops (including user profiles & data) and infrastructure storage
  • Atlantis ILIO Persistent VDI storage optimization software for 1,000 persistent VDI users – 1 Atlantis ILIO virtual machine per Flex Compute node running virtual desktops (8 total) with 1vCPU reserved, 1 vCPU allocated with 30GB of RAM reserved.  

For deployments that are larger than 1,000 users, you can use the IBM FlashSystem 820 with 20TB of usable storage to support up to 4,000 users per 1U array.

IBM Innovation Center Benchmark Testing

The IBM Innovation Center conducted extensive performance, scalability and reliability testing. The testing included measuring:

  1. The storage density and optimization that could be achieved with Atlantis ILIO
  2. Reliability and high availability during server outages
  3. Desktop performance using industry standard benchmarking tools such as LoginVSI 3.7 (Medium workload), ioMeter and PassMark Performance Test 8.0.

Benchmark Testing Summary


 IBM FlashSystem with Atlantis ILIO Persistent VDI

Optimized Virtual Desktop Size

86MB per desktop (99% reduction*)

Storage Density

Up to 4000 users per 1U of Storage

Concurrent Available IOPS Per Desktop

382 IOPS (20-40X more than typical VDI deployment)

Disk Performance

6x Faster Than a MacBook Air (PassMark)

Recovery Time

1 minute 14 seconds






*Percentage reduction measured from an equivalent system without Atlantis ILIO software.

Persistent VDI Test Results

The test results showed that Atlantis ILIO with FlashSystem 820 was able to achieve storage density of up to 4000 users per 1U of storage space, while maintaining a server density of 125 virtual desktops per server (2x Intel Xeon E5-2670 with 256GB RAM). When tested using ioMeter with an industry-standard VDI IO profile (80% write, 20% read, 80% random, 4K blocks with 800GB Test File), the Atlantis ILIO virtual machine was able to deliver 47,825 IOPS per server. With a server density of 125 virtual desktops, this means that each virtual desktop has access to a minimum of 382 available IOPS and the ability to burst up to thousands of IOPS per desktop when needed. High Availability (HA) testing using Atlantis ILIO Persistent VDI 4.1 was able to show automated fail-over and recovery in 1 minute and 14 seconds. Performance testingusing ioMeter, LoginVSI and PassMark showed desktop performance that was 13x faster than a typical physical PC user experience and 6x faster than a MacBook Air with an SSD.

LoginVSI 3.7 Medium Workload User Experience

Persistent VDI response time in miliseconds (LoginVSI 3.7 Medium Workload)

PassMark 8.0 PC Performance Benchmark

Persistent VDI PassMark Performance Test 8.0 benchmark: Atlantis ILIO persistent VDI disk performance compared to PC storage (SSD, SATA Hard Disks)

ioMeter Single Server TestPersistent VDI Single Server ioMeter test (80% write, 20% read, 4K, 80% random, 800GB Test File)

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