Script to back up a Windows EBS volume on EC2 to S3 by snapshot.

Invoke-BackupJob.ps1

#backup a disk by snapshot to S3.
param
(
    [string] $path, #directry to clean of old files
    [int] $diskNumber,
    [string] $ec2VolumeId, #volumn arn in ec2
    [string] $description, 
    [int] $days = 2
);

function aws { & 'C:\Program Files\Amazon\AWSCLI\aws.exe' $args; }

function Snapshot-Disk([int] $diskNumber, [string] $ec2VolumeId, [string] $description)
{
    #un-mount drive before snapshot
    UnMount-Disk $diskNumber;
    Write-Host "aws ec2 create-snapshot --volume-id $ec2VolumeId --description $description"
    $result = (aws ec2 create-snapshot --volume-id $ec2VolumeId --description $description) -join "`n" | ConvertFrom-Json;

    #poll until job is compmleted
    while((Get-SnapshotProgress $result.snapshotId) -lt 100)
    {
        Write-Host "Sleep 60 seconds.";
        Start-Sleep 60; #wait 1 minute
    }
    #mount drive again
    Mount-Disk $diskNumber;
}

function Get-SnapshotProgress([string] $snapshotId)
{
    Write-Host "Get-SnapshotProgress $snapshotId."
    #result is in JSON format. It gets automatically split into a string[] by powerhsell on newlines
    #when it retrieves the return value from the aws cli process. 
    #convert array back to string in order to pass to ConvertFrom-Json
    $result = (aws ec2 describe-snapshots --snapshot-ids $snapshotId) -join "`n" | ConvertFrom-Json;
    $progress = 0;
    if($result.Snapshots.Progress) {
        $progress = [int]$result.Snapshots.Progress.TrimEnd('%');
    }
    Write-Host "Progress: $progress%.";
    return $progress;
}

function UnMount-Disk([int] $diskNumber)
{
    Write-Host "Unmount disk $diskNumber.";
    Get-Disk -Number $diskNumber | Set-Disk -IsOffline:$true;
}

function Mount-Disk([int] $diskNumber)
{
    Write-Host "Mount disk $diskNumber.";
    Get-Disk -Number $diskNumber | Set-Disk -IsOffline:$false;
    Get-Disk -Number $diskNumber | Set-Disk -IsReadONly:$false;
}

function Remove-OldFiles(
    [string] $Path = ".", # directory to clean
    [int] $Days   = 2, #days of grace. files older than $Days will be deleted
    [Switch] $Whatif
)
{
    Write-Host "Clean files from $Path over $Days days old."
    $now = [DateTime]::Now; 
    Get-ChildItem $Path -Recurse | Foreach-Object {
        if( !$_.PsIsContainer -and ($now-$_.LastWriteTime).Days -ge $Days ){
            if( $Whatif ) {
                Write-Output "Remove-Item $($_.FullName)";
            } else { 
                Remove-Item $_.FullName;
            }
        } 
    }
}

& {
    Import-Module Microsoft.PowerShell.Utility
    Write-Host "Begin: $(Get-Date)";
    Snapshot-Disk $diskNumber $ec2VolumeId $description;
    Remove-OldFiles $path $days;
    Write-Host "End: $(Get-Date)";
}

How to Use

• Step 1: write data to volume -- such as SQL Server backup.
• Step 2: Invoke this script

Script Execution

• Dismount EBS volume from Windows
• Create snapshot of volume to S3 - Poll until snapshot is complete
• Mount EBS volume in Windows again
• Clean old files from volume Disk Number comes from Get-Disk cmdlet.

Run as a scheduled job like this (where -path is the Windows filesystem path, -diskNubmer is the mount number in Windows and -ec2VolumneId is the EBS volume in EC2):

powershell.exe -file "C:\Program Files\Utility\Invoke-BackupJob.ps1" -path D:\ -diskNumber 2 -ec2VolumeId vol-XXXXXXXX -description "Important Server Backup" > "C:\Program Files\Utility\log.txt"