Visit Nutanix

Nutanix Connect Blog

Welcome to the Nutanix NEXT community. To get started please read our short welcome post. Thanks!

Showing results for 
Search instead for 
Do you mean 

Nutanix Acropolis File Services (AFS): Performance and Scalability by Design

by Community Manager ‎01-24-2017 11:07 AM - edited ‎01-24-2017 11:11 AM (2,602 Views)



This post authored by Dan Chilton, Sr Solutions Performance Engineer at Nutanix


Nutanix recently released version 5.0 of the Acropolis Operating System and with that release came an exciting Nutanix product feature—Acropolis File Services, or AFS, for short. This new feature deploys like an app on the Nutanix platform. It provides the ability to deploy a robust, enterprise-capable SMB file sharing solution on a Nutanix cluster. By providing this feature within the Nutanix platform, it removes the need to maintain a separate stand-alone network attached storage (NAS)  solution for Windows / SMB  file services.


AFS is a clustered, distributed file server that runs as a set of file server VMs on the Nutanix platform. AFS has performance scalability built into the flexible design. As storage and performance needs grow, AFS can easily scale out or up, while also allowing dynamic load balancing. For more of a deep dive on AFS features and architecture, read our tech note.


The following workloads are well suited to be supported by the Nutanix designed AFS.

  • Windows user home directories
  • Virtual desktop user remote profiles
  • Departmental shares
  • Application shares

In this blog, we discuss file server performance requirements and testing methods, as well as how AFS meets and exceeds these requirements.


One of the first things that customers want to know when considering a file server solution is how well it performs. As someone who focuses on solution performance in my day job, I know how important this is. However, to answer the question, we first need to understand what the customer wants to do with the solution. The customer interactions with the file server constitute the workload.


Here are some example workloads:

  • Copying one large file at a time to the file server.
  • Browsing a list of files in a directory and then reading the desired file.
  • Downloading a file from the file server to the local client desktop.
  • Editing a document with Microsoft Word and then saving the document.
  • Multiple users logging on to virtual desktops that have their remote profiles stored on a file server

We used tools throughout the development and release cycle to test the performance of these workloads and others to make sure that we would perform well for our target use cases. To test workload #1, we used robocopy/copy and paste, #2-#4 Microsoft File Service Capacity Tool or FSCT, and #5 LoginVSI.


Single File Copy Test = Poor Test of Performance


File copy is easy to test (just copy and paste a large file) but it is a poor indicator of file system performance due to a low number of outstanding I/O and the single threaded nature of the workload. This means that a file copy test doesn’t accurately test what the fileserver can do.


Typical real world situations have many clients or applications requesting data concurrently driving a workload. Don’t just take my word for it, check out this discussion from Microsoft OneDrive team member Jose Barreto.




FSCT is a performance test suite based on the analysis of real user home directory operations at Microsoft. It has been used to prove performance by file server vendors including Microsoft, NetApp, and EMC. Some key aspects of FSCT that make it so valuable for simulating customer user home directory environments are:

It tests Active Directory integration, including Windows Domain Controllers, clients, user accounts, authentication, and permissions

  • Users connect to their home directory with multiple sub-directories, for a total of 270 files/folders and ~80MB of data
  • Users execute scenarios that create file service metadata workloads
  • Operations include cmdline file download/upload, Windows Explorer file delete, drag/drop, MS Word file open/close, and save
  • Throughput is measured in user count of concurrent sustained users, instead of IOPS/FileOPs.

We found that AFS provides a solution for home directories that can be scaled up as user count grows.

  • With FSCT, we pushed our file server to the limits and established reliable user connection counts per file server VM (FSVM) node that can be scaled up as needed.
  • We translated this data into the Nutanix Sizing tool to provide quality sizing proposals coupled with room for future growth.
  • The chart below shows the capability of a single AFS file server node in terms of concurrent heavy user workload.



The AFS solution starts with as few as three VMs, but we have successfully tested a solution scaled out to as many as 16 AFS virtual machines on a 16-node cluster. AFS functionality can be added to existing Nutanix clusters to leverage extra storage capacity or deployed as a standalone file server cluster. 


You can scale out small four vCPU and 16 GB RAM AFS VM nodes to support thousands of users by distributing the load across AFS nodes.




Why LoginVSI


We configured LoginVSI, a popular, industry-standard VDI sizing tool, to store the virtual desktop user remote profiles on the AFS solution. We also used Citrix Profile management, a robust enterprise VDI deployment suite. The workload includes Windows OS operations and applications including Microsoft Outlook.


With VDI profiles, the AFS server consumes cycles mainly during the boot phase; once the desktops are booted, they consume most of the CPU and RAM cycles. Accordingly, to gauge AFS performance, we focused on average logon time as the key metric (of course, less is more when it comes to logon time). We wanted to see if logon time increased with clients connecting to AFS file shares to read their profiles at boot up, rather than to the local c:\drive.


We found that we could easily support a 400 virtual desktop deployment with our smallest AFS cluster. As shown in the chart below, the total user desktop logon time was 7.2 seconds for local c:\drive and 6.8 for remotely stored profile. (Note that these logon times are typical for LoginVSI virtual desktops and should not be confused with individual I/O response times, which are often in the ms and us range.)




Why Choose AFS? Performance Scalability by Design


  • Scale Out—Clustered by design with at least three nodes, AFS currently supports up to 16 nodes. Workloads can be distributed evenly across small or large Nutanix clusters. You can add more file server VMs as additional storage or compute are needed.
  • Scale Up—Recognizing that some file services workloads require large amounts of processing (CPU) and caching (memory), AFS nodes can scale up as requirements grow by adding additional vCPUs and RAM.
  • Load Balancing–As file data grows, the storage or processing demands sometimes cause a hot node. AFS easily solves this by rebalancing data and processing across nodes.
  • Analytics-driven—A fine-grained analytics engine built into AFS continually analyzes the storage and performance consumption of the file server. From this analysis, AFS recommends scaling out, scaling up, or rebalancing. This feature can reduce TCO by minimizing administration time and performance troubleshooting.

Our testing shows that the flexible, clustered design of AFS can provide the performance and scalability enterprises need for the most demanding SMB file sharing environments, all without the added expense of a standalone NAS appliance. Talk to your Nutanix partner to request a demo for AFS and leave the file storage and management to us.


If you are new to Nutanix, we invite you to start the conversation on how the Nutanix Enterprise Cloud Platform can work for your IT environment. Send us a note at info@nutanix.com or follow us on Twitter and join the conversation in our community forums.


Disclaimer: This blog may contain links to external websites that are not part of Nutanix.com. Nutanix does not control these sites and disclaims all responsibility for the content or accuracy of any external site. Our decision to link to an external site should not be considered an endorsement of any content on such site.



Perth Radiological Clinic (PRC) comprises 70 radiologists who provide leading diagnostic medical imaging services to a number of healthcare organisations and their patients from 19 locations across Perth. In his role as Development and Infrastructure Manager, George Hewitt manages PRCs data centre, network and applications. We recently spoke with George about PRCs implementation of Nutanix to enable a reliable data centre environment with the performance and storage required to operate critical systems. Here are the highlights:


Q: What issues did PRC face with its former IT infrastructure?

We operate two data centres. These are mirror images, where one acts like a fail-safe in case we experience any outages or failures. Its a necessary safety net for a real-time business like ours; our systems must be always-on so that our partners and customers can access critical client imaging and reports to inform their treatments.


Both data centres previously ran on storage area networks (SANs) which began experiencing performance and scalability issues. They were becoming slow, and configuration and management was increasingly complicated. Getting data off the servers wasnt as efficient as we needed it to be.


Adding to that, we got to a point where executing a new project would be difficult as we lacked the resources to dedicate to it. This became a bigger problem when PRC decided to move from storing seven yearsworth of customer data to 10.


Q: Why did you select Nutanix?

As well as needing a better way of storing, accessing and using 10 yearsworth of medical images and associated data, we required a reliable platform that could run our critical systems. That includes a web app which provides our customers including emergency departments, general practitioner clinics, and so on online access to reports and imaging as soon as they become available; a Radiological Information System (RIS), which is our industrys ERP equivalent; and a Pictures Archiving and Communications System (PACS) where all images are stored and replicated. These are high-demand systems that must always be available to us and our clients so we can ensure the best possible treatment of patients.


After meetings with BEarena and Nutanix, we realised Nutanixs simplicity, scalability and performance would give us the ability to ensure these applications are working as intended, allowing us to focus on delivering value to the organisation rather than maintaining the data centre.


Q: What benefits have you experienced since implementing Nutanix?

Nutanix has played an important part in our 25 per cent growth over the last year. As well as providing stability for our systems, it has allowed us to expand our data centre to match new and rising business requirements. Whenever we need more compute, storage, and memory, we just add another node to the stack and it integrates itself very quickly. It requires minimal interference from us, and maintenance is very simple Nutanixs Prism management console removes all complexity; in the rare instance there is an issue, it can be identified, isolated and resolved quickly. That saves a lot of time, which has allowed me and the rest of the team to focus more energy on more important tasks. And after all, time means productivity, and productivity translates to the bottom line.


Q: Can you tell us about some of the new projects PRC has been able to pursue?

Historically, RIS systems, and therefore Radiology departments, haven’t been the most integrated services, but we’ve recently started providing connectivity between providers in terms of enabling electronic ordering between us and the hospitals we service. The benefits of doing this can be felt everywhere – there is less data entry, more accurate information and faster result delivery, all of which enhances the quality of patient care.  


We have also been able to very easily manage the merger of another radiology company into ours and we opened a radiology department in a hospital in Midland, Perth. Knowing we had the scalability of Nutanix made it a safe bet as we could handle the increased amount of imaging that we needed to ingest and store.


Q: What role did Nutanix partner, BEarena, play in your transition?

I cant speak highly enough of BEarena. The teams support has been excellent they are extremely responsive and available any time weve needed them. They have ensured everything is working as it should, and are proactive in suggesting areas in which we can further capitalise on the technology.


This post was authored by Fiona Partlow, Senior Manager, Global Customer Reference Program at Nutanix



One of the fun things about participating in an online community is developing a community identity. One way to do that is with a personalized avatar.

Read More: How to Change Your Community Profile Avatar