#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : iSCSI targets disconnect, or disks appear offline after a reboot
    Fix   : Set the SAN policy and make the connection persistent
    Source: https://jbtecwiz.com/support/srv-sto-iscsi

    Run as     : Elevated PowerShell
    Expect     : 25 minutes
    Risk       : medium
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    Disks come back offline after a reboot.

    HOW TO UNDO IT
    Set-StorageSetting -NewDiskPolicy OfflineShared restores the default.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 6"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  iSCSI targets disconnect, or disks appear offline after a reboot' -ForegroundColor White
Write-Host '  Set the SAN policy and make the connection persistent' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: medium   Reversible   25 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Check the current SAN policy. On Server it defaults to Offline Shared, which is why every new disk arrives offline.' -Why 'This is by design and protects clustered storage from being mounted by two nodes at once. On a standalone server with dedicated LUNs it is simply an obstacle, and it is the cause of almost every "my iSCSI disks are offline again" report.' -Command {
    Get-StorageSetting | Format-List NewDiskPolicy
}

Invoke-Step -Number 2 -Do 'On a standalone server with dedicated LUNs, change it.' -Command {
    Set-StorageSetting -NewDiskPolicy OnlineAll
}

Invoke-Step -Number 3 -Do 'On a cluster node, leave the policy alone -- the cluster service brings disks online. Changing it there causes corruption.' -Manual

Invoke-Step -Number 4 -Do 'Bring the disks online and clear the read-only flag.' -Command {
    Get-Disk | Where-Object OperationalStatus -eq 'Offline' | Set-Disk -IsOffline $false
    Get-Disk | Where-Object IsReadOnly -eq $true | Set-Disk -IsReadOnly $false
}

Invoke-Step -Number 5 -Do 'Make the iSCSI connection persistent so it re-establishes at boot.' -Command {
    Get-IscsiTarget | Connect-IscsiTarget -IsPersistent $true -IsMultipathEnabled $true
    Get-IscsiSession | Format-Table TargetNodeAddress,IsPersistent,IsConnected
}

Invoke-Step -Number 6 -Do 'Set the volumes to mount by GUID or a persistent letter so drive letters do not move.' -Command {
    mountvol
}

Write-Rule "  Confirm it worked"
Show-Prose 'After a reboot the disks come back online with the same letters.' 'White'
Write-Host ''
if (-not $DryRun) {
    Get-Disk | Format-Table Number,FriendlyName,OperationalStatus,IsOffline,BusType
    Get-Volume | Format-Table DriveLetter,FileSystemLabel,HealthStatus
}

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/srv-sto-iscsi' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Set-StorageSetting -NewDiskPolicy OfflineShared restores the default.' 'DarkGray'
Write-Rule