Enhancing High Availability with Amazon FSX for Windows File Server

In this tutorial, I’ll walk you through two deployment options for Amazon FSX for Windows File Server, explore the architecture of both, and introduce the concept of continuously available shares for ensuring high availability in your SQL Server workloads during failovers.

File System Deployment Options

Before we dive into the world of continuously available shares, let’s briefly examine the two deployment options available with Amazon FSX for Windows File Server.

Single Availability Zone (AZ) Deployment

In a single AZ deployment, Amazon FSX still ensures that your infrastructure is continually monitored and addresses hardware failures. This takes the management burden off your shoulders, allowing you to focus on your applications while AWS takes care of the infrastructure. Your data is replicated within the single availability zone, offering some level of resiliency.

Multi-AZ Deployment

In a multi-AZ deployment, you get all the benefits of the single AZ deployment, plus the added redundancy of replicating data across multiple availability zones. This configuration is highly recommended for applications that require a higher level of availability. If one availability zone becomes unavailable, your workloads can seamlessly failover to another.

File System Architecture

Now, let’s explore the architecture of these two deployment options.

Single AZ File System

In a single AZ file system, Amazon FSX is deployed within a single availability zone. While it provides a durable file system, it lacks the high availability of multi-AZ setups. If there’s an issue in the availability zone where your FSX is deployed, you could lose access to it from other availability zones and on-premises networks.

Multi-AZ File System

A multi-AZ file system is designed for high availability. It involves redundant infrastructure deployed across two availability zones. If there’s an issue in one availability zone, you still have access to your file system from the other, as well as from on-premises networks. Automatic failover ensures that your workloads remain accessible.

Continuously Available Shares

One of the key features that make multi-AZ deployments even more resilient is the concept of “continuously available shares.” This feature is based on Microsoft Windows Server’s continuously available file shares, which ensure that file shares remain accessible to clients even when a node in the cluster fails.

Continuous availability can be particularly important for workloads that require highly available file shares for critical applications. However, it’s not suitable for all workloads. It’s not enabled by default on Amazon FSX for Windows File Server because it introduces a minimum performance impact. It should be enabled on a share only when necessary, such as for SQL Server workloads, where continuous access to files is crucial.

Demonstrating Continuously Available Shares

Let’s see how you can enable or disable continuously available shares using PowerShell.

PowerShell Administration

  • Ensure your server is joined to the domain where your Amazon FSX file share exists.
  • Use PowerShell to administer your FSX file system. You can connect to the FSX endpoint or use the Invoke-Command to run FSx remote admin commands.
  • To enable continuous availability for a share, run the command to set it to “true.”
Invoke-Command -ComputerName <FSX Endpoint> -ScriptBlock {
    Set-SmbShare -Name <Share Name> -ContinuouslyAvailable $true
  • To disable continuous availability for a share, run the command to set it to “false.”
Invoke-Command -ComputerName <FSX Endpoint> -ScriptBlock {
    Set-SmbShare -Name <Share Name> -ContinuouslyAvailable $false

In the demo, I’ve changed my default share from “not continuously available” to “continuously available.” This allows SQL Server to experience smoother failovers during maintenance or hardware issues.

Continuously available shares provide transparency during failovers and can be essential for applications that require uninterrupted access to files.

By understanding how continuously available shares work and having the flexibility to enable or disable them, you can tailor your Amazon FSX for Windows File Server to meet the specific high availability needs of your workloads.

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