Azure Storage Files is a sub service of Azure Storage Accounts. It offers fully managed file shares in the cloud that are accessible via the industry standard Server Message Block (SMB) protocol (also known as Common Internet File System or CIFS). The cloud File shares can be mounted concurrently by cloud or on-premises deployments of Windows, Linux, and macOS machines.

At a recent cloud migration engagement, a key requirement was the automation of Azure storage file sync/copy to a secondary storage account in the same Azure subscription to help mitigate against accidental file deletion.

As of this writing, Azure Backup and snapshots are not supported for Azure File Storage. Microsoft recommends using Robocopy, the AzCopy CLI tool or a 3rd party backup tool to copy or backup Azure File storage data. Robocopy needs a UNC path,which will require the Azure Storage File Share be mapped as a local network drive for local access to the files. This option did not meet the requirement for automation. The AzCopy tool, does not require local access to a mapped drive, but needs to be installed on the Azure VM or on-premise server.

The ideal automated solution should be deployed in Azure and in addition, trigger email notifications with details of the copied file storage items after processing the files. I developed the following PowerShell function to meet these requirements. Hopefully, Azure Backup and Snapshot support for Azure File Storage will be rolled out soon. A feature request for File Storage Account backups or snapshots currently exists at this link.

This function (which can also be downloaded at my GitHub Repository) loops through the existing file shares and directories, then copies the existing files based on the last modified time stamp property being greater than one hour. I deployed this solution as a Time triggered PowerShell Azure Function App executed once at the top of every hour.

At this time, I don’t think Azure Function Apps support Azure Key Vault for secure authentication to Azure( I could be wrong though and stand corrected). For this Function App to authenticate with Azure, I generated and uploaded an AES256 Encryption key file used to encrypt/decrypt the password in order to generate an encrypted standard password file to be referenced by the function App. The following screen shot displays the Function App settings for the encrypted Azure logon password, Azure credential username, encrypted sendgridpassword and the local time zone.

<#
.SYNOPSIS
   The Copy-AzureStorageFilesFunctionApp Function copies files from one storage account to another in the same subscription.
.DESCRIPTION
   The Copy-AzureStorageFilesFunctionApp Function copies files from one storage account to another in the same subscription. At this time while developing this function 9/13/2017,
   Azure Backup and snapshots are not supported for Azure File Storage.
   This function is written to be deployed as an Azure Function App and executed based on an hourly time trigger.
   It take a Resource Group name and subscription name as parameters.
   An email notification is sent to the Subscription Admin with a list of the items copied.
.PARAMETER SubscriptionName
        Subscription to be processed.
.PARAMETER ResourceGroupName
        ResourceGroupName of the source and target storage accounts.
.EXAMPLE
        Copy-AzureStorageFilesFunctionApp            
.FUNCTIONALITY
        PowerShell Language
#>
[CmdletBinding()]

param(
    [parameter(Mandatory = $false)]
    [string]$SubscriptionName = "Trial",
    [parameter(Mandatory = $false)]
    [string]$ResourceGroupName = "RGVPN"
       
)

#region Azure Logon
$Username = $env:AzureUsernameCredential
$EncryptedPassword = $env:AzurePasswordCredential
$AESKeyPath = "D:\home\site\wwwroot\TimerTriggerPowerShell1\bin\AESKey.key"
$SecurePassword = ConvertTo-SecureString -String $EncryptedPassword -Key (Get-Content -Path $AESKeyPath)
$Credential = New-Object -TypeName System.Management.Automation.PSCredential($Username, $SecurePassword)
Login-AzureRmAccount -Credential $Credential
Select-AzureRmSubscription -SubscriptionName $SubscriptionName

#endregion

#region create email creds
$Smtpserver = "smtp.sendgrid.net"
$From = "jack.bauer@democonsults.com"
$To = "jack.bauer@democonsults.com"
$Port = "587"
$sendgridusername = "azure_a8a3e2815501214fbc3adf4ad15cc315@azure.com"
$sendgridPassword = $env:SendGridPasswordCredential
$emailpassword = ConvertTo-SecureString -String $sendgridPassword -Key (Get-Content -Path $AESKeyPath)
$emailcred = New-Object System.Management.Automation.PSCredential($sendgridusername, $emailpassword)
#endregion

#Initialize storage variables
$StorageAccountName = "storevpn0518"
$DestStorageAccountName = "store0518"
$DestResourceGroupName = "RGXavier"
$Store = Get-AzureRmStorageAccount -ResourceGroupName $ResourceGroupName -Name $StorageAccountName
$Shares = Get-AzureStorageShare -Context $Store.context
$Deststore = Get-AzureRmStorageAccount -ResourceGroupName $DestResourceGroupName -Name $DestStorageAccountName
$Items = @()


foreach ($Share in $Shares) {
    $Directories = Get-AzureStorageFile -Share $Share

    foreach ($Directory in $Directories) {
        if ((Get-AzureStorageShare -Name $Share.Name -Context $Deststore.Context -ErrorAction SilentlyContinue) -eq $null) { 
            
            New-AzureStorageShare -Name $Share.Name -Context $Deststore.Context    
        }
        if ((Get-AzureStorageFile -ShareName $Share.Name -Context $Deststore.Context -Path $Directory.Name -ErrorAction SilentlyContinue) -eq $null) {
            New-AzureStorageDirectory -ShareName $Share.Name -Context $Deststore.Context -Path $Directory.Name               
                
        }
        $sourcefiles = Get-AzureStorageFile -ShareName $Share.Name -Context $Store.context -Path $Directory.Name | Get-AzureStorageFile        
        $destfiles = Get-AzureStorageFile -ShareName $Share.Name -Context $Deststore.Context -Path $Directory.Name -ErrorAction SilentlyContinue `
            | Get-AzureStorageFile
        if ($destfiles.count -eq 0) {
            foreach ($sourcefile in $sourcefiles) {
                Start-AzureStorageFileCopy -SrcShareName $Share.Name -SrcFilePath ($Directory.Name + "/" + $sourcefile.Name)  -Context $Store.Context `
                    -DestShareName $Share.Name -DestFilePath ($Directory.Name + "/" + $sourcefile.Name) -DestContext $Deststore.Context -ErrorAction SilentlyContinue
            }
        }
        else {
            foreach ($sourcefile in $sourcefiles) {
                $sourcefile.FetchAttributes()
                if ($sourcefile.Properties.LastModified.LocalDateTime -gt ((Get-Date).AddMinutes(-60)) ) {
                    Start-AzureStorageFileCopy -SrcShareName $Share.Name -SrcFilePath ($Directory.Name + "/" + $sourcefile.Name)  -Context $Store.Context `
                        -DestShareName $Share.Name -DestFilePath ($Directory.Name + "/" + $sourcefile.Name) -DestContext $Deststore.Context -Force -ErrorAction SilentlyContinue

                    $copyState = Get-AzureStorageFileCopyState -ShareName $Share.Name -FilePath ($Directory.Name + "/" + $sourcefile.Name) -Context $Deststore.Context `
                        -WaitForComplete -ErrorAction SilentlyContinue
                    $Items += $copyState
                }
            }
        }
    }
}

#region process email

$a = "<style>"
$a = $a + "BODY{background-color:white;}"
$a = $a + "TABLE{border-width: 1px;border-style: solid;border-color: black;border-collapse: collapse;}"
$a = $a + "TH{border-width: 1px;padding: 10px;border-style: solid;border-color: black;}"
$a = $a + "TD{border-width: 1px;padding: 10px;border-style: solid;border-color: black;}"
$a = $a + "</style>"
$body = ""
$body += "<BR>"
$body += "These" + " " + ($Items.count) + " " + "file storage items were processed for copy. Thank you."
$body += "<BR>"
$body += "<BR>"
$body += $Items | Select-Object -Property Status, @{"Label" = "Completion Time"; e = {$_.CompletionTime.LocalDateTime}}, @{"Label" = "Item"; e = {$_.Source.AbsolutePath}} | ConvertTo-Html -Head $a
$body = $body |Out-String
$subject = "These items were processed for copy."
if ($Items -ne $null) {
    Send-MailMessage -Body $body `
        -BodyAsHtml `
        -SmtpServer $smtpserver `
        -From $from `
        -Subject $subject `
        -To $to `
        -Port $port `
        -Credential $emailcred `
        -UseSsl
}
#endregion

The following screen shot displays a list of copied files embedded in an email notification after code execution.