When implementing high-availability architectures on AWS EC2 Windows instances, one critical pain point emerges: how to maintain synchronized file systems across multiple servers. Traditional approaches like mounting the same EBS volume to multiple instances simply don't work due to AWS's fundamental storage limitations.

Let's examine why common approaches fail:

// Attempting to attach same EBS to multiple instances
aws ec2 attach-volume \
    --volume-id vol-1234567890abcdef0 \
    --instance-id i-01474ef662b89480 \
    --device /dev/sdf
// This will fail for second instance with:
// "Volume is already attached to another instance"

Even NFS solutions face challenges due to AWS's network architecture and Windows compatibility issues. S3-based solutions like s3fs introduce unacceptable latency for real-time file operations.

Option 1: AWS FSx for Windows File Server

The most robust native solution is AWS FSx:

# PowerShell deployment example
New-FSxWindowsFileSystem 
    -FileSystemType WINDOWS 
    -StorageCapacity 300 
    -SubnetId subnet-01234567890abcdef 
    -SecurityGroupIds sg-01234567890abcdef 
    -ThroughputCapacity 16 
    -ActiveDirectoryId d-0123456789

Benefits include:
- Native SMB protocol support
- Built-in redundancy
- Automatic backups
- AD integration

Option 2: Third-Party Distributed File Systems

For more flexibility, consider solutions like Microsoft DFS:

# DFS Namespace creation
Import-Module DFSN
New-DfsnRoot -TargetPath "\\server1\share" -Type DomainV2 -Path "\\domain\namespace"
Add-DfsnFolderTarget -Path "\\domain\namespace\folder" -TargetPath "\\server2\share"

Option 3: GlusterFS Windows Implementation

While primarily Linux-focused, GlusterFS has Windows compatibility:

# Sample gluster volume configuration
volume posix
    type storage/posix
    option directory /data/export
end-volume

volume locks
    type features/locks
    subvolumes posix
end-volume

volume brick
    type performance/io-threads
    option thread-count 16
    subvolumes locks
end-volume

When evaluating solutions, test these key metrics:

• Latency: Should be <5ms for most operations
• Throughput: Minimum 100MB/s for web content
• Consistency: Strong consistency required for SVN repositories

Before deployment:

When architecting high-availability solutions on AWS EC2 with Windows Server instances, maintaining consistent file system state across instances becomes critical. Traditional approaches like direct EBS sharing or NFS present significant limitations in AWS environments.

EBS volumes can only be attached to single EC2 instances simultaneously, making real-time file sharing impossible. While NFS might seem logical, AWS network configurations and Windows NFS client limitations often create performance bottlenecks and reliability issues.

For web server document roots like C:/htdocs/ or version control repositories (C:/Repositories), consider these proven approaches:

Option 1: AWS FSx for Windows File Server

The fully managed solution that provides multi-AZ redundancy:

# PowerShell to map network drive on EC2 instances
New-PSDrive -Name "Z" -PSProvider FileSystem -Root "\\your-fsx-dns-name\share" -Persist

Option 2: Third-Party Distributed File Systems

Solutions like GlusterFS or SMB3 Scale-Out File Server cluster:

# Server configuration (node1)
Add-WindowsFeature -Name FS-FileServer, FS-Data-Deduplication

# Client mounting
net use Z: \\cluster-fs\webroot /persistent:yes

When deploying shared file systems in AWS:

• Place instances and file servers in same subnet/VPC for low-latency access
• Configure proper IAM roles for secure access
• Implement monitoring for file system performance metrics

For scenarios requiring eventual consistency rather than real-time sharing:

# PowerShell sync script for document roots
$source = "C:\htdocs"
$destination = "\\backup-server\webroot"
robocopy $source $destination /MIR /R:1 /W:1 /LOG:C:\sync.log