Storage + VDI: the results speak for themselves at Nuance Communications

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1 Storage + VDI: the results speak for themselves at Nuance Communications HPE 3PAR StoreServ All-Flash helps Nuance Communications build the right storage solution for a demanding high-performance computing environment, plus enhance their capabilities by supporting with an advanced VDI implementation. Contents E xecutive summary... 2 S peaking of challenges... 2 R esisting the easy way out... 2 I nnovating and getting the most out of best practices... 3 T he test environment... 3 U nbeatable... 5 A bout the company Nuance Communications... 6 Technical white paper

2 Technical white paper Page 2 Executive summary Headquartered in Burlington, MA, Nuance Communications (Nuance) has been a pioneer in speech and language technologies for more than 30 years. The company s Research operations rely extensively on a High Performance Computing (HPC) environment that must keep pace with increasingly complex use cases and performance demands. These demands on every aspect of the IT environment are continually increasing, often testing the limits of existing technology infrastructure. Because Nuance was familiar with HPE s all-flash solutions and the performance advantages that flash brings over physical media, the company selected the HPE 3PAR StoreServ All-Flash for its next-generation storage solution. After seeing immediate performance enhancements to core HPC workloads with this change, Nuance decided to explore other use cases using the product. Specifically, Nuance implemented an all-linux Virtual Desktop Infrastructure (VDI) solution, using the HPE 3PAR StoreServ All-Flash array with Red Hat 6.6 KVM version This paper describes how Nuance deployed its VDI solution. It also defines some of the key benefits, including vastly expanded access to virtual machines in the company s data center, high levels of security, and lower space/power consumption that the company realized from this specific solution. Speaking of challenges Determining how written text is converted to speech is a hugely challenging task in itself. Languages are modeled. Samples of real spokenlanguage are recorded and analyzed to create a language model. The higher the quality of the language model, the better the experience of the user, especially in complex interactions. Nuance s High Performance Computing Group is tasked with providing services to the researchers who work to constantly improve the model in 40 languages, while also making provisions for regional and sometimes localized accents. It is a massive undertaking which involves processing 1.2 terabytes of data per day. In 2014, Nuance realized that the standard storage array it was using for its HPC environment was costly and inefficient both in terms of space and power consumption. After evaluating a number of storage vendors and solutions, the company selected HPE 3PAR StoreServ All- Flash storage for its ability to deliver results more quickly, while reducing space and power consumption. Nuance also felt sure that the dedupe capabilities of the HPE 3PAR all-flash solution would help reduce the number of copies needed within the VDI and therefore result in much greater efficiencies. Nuance was well aware of the unique computing needs of its researchers worldwide. To respond to these requirements, Nuance adopted a holistic approach based on a VDI solution that allowed researchers from around the world to use thin clients to access virtual machines in the company s data center. Because the clients only provided a GUI into the data center with no actual data being moved, this solution also ensured a high level of security. Nuance selected Red Hat 6.6 KVM version 12.1 for its VDI solution and paired it with the HPE 3PAR StoreServ storage solution. Resisting the easy way out The Nuance team knew that their new solution would deliver specific and impressive enhancements. But, team members knew they could do better if they also took the time to implement a series of environment-specific best practices as part of the solution s implementation. These best practices were built around Nuance s goals and included approaches such as: User virtual machines (VMs) on clustered storage so they could be migrated around during maintenance or for load balancing Application VMs running on higher-performance Intel processors for performance The team wanted to explore two main questions: 1. Did initial high dedupe rates necessarily have to slow down as changes were made to each user s virtual machine? 2. Was it possible to reduce the total number of VMs in the environment? In the initial set-up, the VMs served as the users graphical desktop in the R&D environment. They were not linked clones or snapshots of a master image, but were a copy of the master. This meant that each user has at least one machine. The ability to reduce the number of machines would reduce the cost to store the virtual desktops without giving up performance.

3 Technical white paper Page 3 Innovating and getting the most out of best practices As most of the Nuance VMs use the Linux operating system (OS), the team looked at minimizing storage of multiple copies of the OS data. Unfortunately, the user data (or the non-os portion) was very difficult to dedupe, thus creating a major challenge. So the Nuance team decided to separate the OS from the ever-changing user data. A second area that showed promise was an initiative to make a single copy of the OS and have all users simply look at that one using a pointer approach. These best practices then were to be fully tested to determine the results each approach would deliver in the Nuance VDI environment. It was hoped the tests would prove to Nuance that they could rely on the performance of the HPE 3PAR StoreServ All-Flash arrays as the means to achieve greater efficiency and performance. The test environment The test environment consisted of 4 HPE C7000 BL460c G6 blade servers with dual Flex10 and SAN connections, so they had 2 x 10Gbe and 2 x 8FC. The storage backing for test was a 3PAR 7450 with 48 x 1.9TB SSD drives. The test environment only used CentOS6.6 as the guest OS. All hypervisors were running RHEL 6.6 and GPFS cluster file systems. This contrasts with the production environment that has 3 C7000 blade chassis with 16 AMD based servers each as hypervisors. Each server has dual Flexfab connections that are split 2 x 6G for network and 2 x 4G for SAN. The storage backing for production is a 3PAR with 420 x 600GB FC drives. Production guests run a mixture of CentOS5.x and CentOS6.x variants. Tests for latency and IOPs were performed using various access layers. These layers include a standard Linux file system, clustered file system and no file system, giving the VM direct access to the LUN. Nuance completed testing using four different access methods. 1.9TB cmlc SSDs were used in all testing. The testing results from each access method are described below. Shared File System Using a standard Linux file system, the SAN storage is presented to the hypervisor as a normal block device. The CPG was set for RAID5. The hypervisor builds a file system on top of the block device and creates VM image files (QCOW) inside the file system. Strength: Ease in managing file-based images. The VMs can be shut down or a snapshot is created for backup. Weakness: The VM cannot be live migrated to another hypervisor without a shutdown/copy/reboot. Space management between hypervisors has to be taken into consideration as there will be pockets of unused locked storage on each server. This method also does not provide the fastest performance to what the VM thinks is its local disk.

4 Technical white paper Page 4 Clustered File System Strength: Provides the ability to perform live migrations without a reboot. Space management is simplified because all hypervisors share the same storage. Weakness: Cost and complexity of managing a clustered solution. Also, the loss of the cluster causes the failure of all VMs creating a SPOF. As with the previous test, the CPG was set for RAID5. Since Nuance was trying to create a higher-performance storage solution for the virtual machines, NFS and iscsi-mounted storage were not tested. VM Direct to SAN Direct access to SAN volumes from virtual machines Strength: This solution gives the best performance in terms of management cost. A 30GiB 3PAR Virtual Volume is created for each virtual machine and presented to the hypervisor host. This volume is then presented to the VM as its local disk. If the VM is to be live migrated to another hypervisor, the storage volume must be presented to the new hypervisor before the migration. Weakness: Creating volumes and presenting them to the correct hypervisor hosts are the management issues that must be dealt with for this solution.

5 Technical white paper Page 5 Hypervisor Direct to SAN Tests were performed on the hypervisor s access to the shared SAN volumes to give a baseline of what a physical machine s performance would be. RESULTS TEST DEDUPE THIN FULL # VOLS # VMs READ BW WRITE BW READ IOPS/K WRITE IOPS/K Shared Yes Yes Shared Yes GPFS Yes Yes GPFS Yes VM direct Yes Yes VM direct Yes Hypervisor Yes Yes Hypervisor Yes This test does show the massive benefit of using the virtual machine approach and of providing each virtual machine with its own SAN volume. Unbeatable The Virtual Desktop Infrastructure (VDI) adopted by Nuance provided strong benefits to the company, including vastly expanded access to VMs in the company s data center with high levels of security. The combined Red Hat KVM VDI HPE 3PAR StoreServ All-Flash solution also reduced space and power consumption. Testing also showed that all VM approaches were superior to the physical machine approach for deduplication. While each access or layer approach delivered different results and had different strengths and weaknesses, all were able to prove themselves superior to physical machines in terms of dedupe, thereby reducing the number of copies needed and the amount of storage used.

6 Technical white paper Page 6 About the company Nuance Communications Headquartered in Burlington, MA, Nuance Communications (Nuance) has been a pioneer in speech and language technologies for more than 30 years. Best known for its Dragon line of speech recognition products, the company has created data centers that host billions of speech transactions every month in over 40 languages from hundreds of applications. Nuance continuously expands its research grid to explore this avalanche of data. In addition, the company s researchers are experts in the fields of speech recognition, statistical modeling, deep machine learning, and linguistics. They use these computational and data resources to continuously advance the boundaries of what can be done with speech technology. Current applications for consumers and companies include: Personal assistant solutions that enable people to communicate with their devices on human terms Document creation solutions that power Dragon NaturallySpeaking develop a highly personalized speech recognition solution for each user without explicit training Medical dictation solutions that generate millions of reports every day Transcription solutions that accurately convert the spoken words in conversational speech, particularly voic s, into text Learn more at hpe.com/3par StoreServ Sign up for updates Copyright 2016 Hewlett Packard Enterprise Development LP. The information contained herein is subject to change without notice. The only warranties for Hewlett Packard Enterprise products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. Hewlett Packard Enterprise shall not be liable for technical or editorial errors or omissions contained herein. 4AA6-5104ENW, September 2016