Event ID 1018: Database I/O Performance Degraded

# Check Exchange database I/O performance counters
$server = $env:COMPUTERNAME

$counters = @(
    "\$server\MSExchange Database ==> Instances(*)I/O Database Reads (Attached) Average Latency",
    "\$server\MSExchange Database ==> Instances(*)I/O Database Writes (Attached) Average Latency",
    "\$server\MSExchange Database ==> Instances(*)I/O Log Writes Average Latency",
    "\$server\MSExchange Database ==> Instances(*)I/O Database Reads (Attached)/sec",
    "\$server\MSExchange Database ==> Instances(*)I/O Database Writes (Attached)/sec"
)

Write-Host "Collecting I/O statistics (30 seconds)..." -ForegroundColor Cyan

Get-Counter -Counter $counters -SampleInterval 5 -MaxSamples 6 |
    ForEach-Object { $_.CounterSamples } |
    Where-Object { $_.CookedValue -gt 0 } |
    Select-Object @{N='Counter';E={$_.Path.Split('')[-1]}},
                  @{N='Instance';E={$_.InstanceName}},
                  @{N='Value';E={[math]::Round($_.CookedValue,2)}} |
    Sort-Object Counter, Instance | Format-Table -AutoSize

# Monitor physical disk metrics
$diskCounters = @(
    "\$server\PhysicalDisk(*)Avg. Disk sec/Read",
    "\$server\PhysicalDisk(*)Avg. Disk sec/Write",
    "\$server\PhysicalDisk(*)Current Disk Queue Length",
    "\$server\PhysicalDisk(*)Disk Reads/sec",
    "\$server\PhysicalDisk(*)Disk Writes/sec",
    "\$server\PhysicalDisk(*)% Disk Time"
)

Get-Counter -Counter $diskCounters -SampleInterval 5 -MaxSamples 3 |
    ForEach-Object { $_.CounterSamples } |
    Where-Object { $_.InstanceName -ne "_total" -and $_.CookedValue -gt 0 } |
    Select-Object InstanceName, @{N='Counter';E={$_.Path.Split('')[-1]}},
                  @{N='Value';E={[math]::Round($_.CookedValue,4)}} |
    Format-Table -AutoSize

# Convert seconds to milliseconds for latency
Write-Host "`nNote: Avg. Disk sec values are in seconds. Multiply by 1000 for ms." -ForegroundColor Yellow
Write-Host "Target: < 0.020 sec (20ms) for reads/writes"020 sec (20ms) for reads/writes" -ForegroundColor Yellow

# Check for database page faults (indicates memory pressure affecting I/O)
$cacheCounters = @(
    "\$server\MSExchange Database(*)Database Page Fault Stalls/sec",
    "\$server\MSExchange Database(*)Database Cache Size (MB)",
    "\$server\MSExchange Database(*)Database Cache % Hit"
)

Get-Counter -Counter $cacheCounters -SampleInterval 2 -MaxSamples 5 |
    ForEach-Object { $_.CounterSamples } |
    Where-Object { $_.CookedValue -ne 0 } |
    Format-Table Path, @{N='Value';E={[math]::Round($_.CookedValue,2)}} -AutoSize

# Check volume information
Get-Volume | Where-Object {$_.DriveLetter} |
    Select-Object DriveLetter, FileSystemLabel, FileSystem,
    @{N='SizeGB';E={[math]::Round($_.Size/1GB,2)}},
    @{N='FreeGB';E={[math]::Round($_.SizeRemaining/1GB,2)}},
    @{N='PercentFree';E={[math]::Round(($_.SizeRemaining/$_.Size)*100,1)}} |
    Format-Table -AutoSize

# Low free space (<20%) can impact performance
Write-Host "`nWarning: Volumes below 20% free space may have degraded performance" -ForegroundColor Yellow

# List Exchange installation and database paths that should be excluded
$ExInstall = (Get-ItemProperty 'HKLM:SOFTWAREMicrosoftExchangeServer15Setup').MsiInstallPath
Write-Host "Exchange Install Path: $ExInstall" -ForegroundColor Cyan

# Get database and log paths
Get-MailboxDatabase | Select-Object Name, EdbFilePath, LogFolderPath |
    Format-Table -AutoSize

# Common paths that MUST be excluded from AV:
Write-Host "`n=== Required AV Exclusions ===" -ForegroundColor Yellow
Write-Host "1. Database files (*.edb)"
Write-Host "2. Transaction log files (*.log)"
Write-Host "3. Checkpoint files (*.chk)"
Write-Host "4. Content index folders"
Write-Host "5. Exchange install folder: $ExInstall"$ExInstall"
Write-Host "6. Cluster quorum disk (if DAG)"

# Verify AV process isn't consuming disk I/O
Get-Process | Where-Object {
    $_.ProcessName -match "scan|antivirus|defender|symantec|mcafee|trend|sophos"
} | Select-Object Name, @{N='CPU';E={$_.CPU}},
    @{N='IO_Read_MB';E={[math]::Round($_.ReadTransferCount/1MB,2)}},
    @{N='2)}},
    @{N='IO_Write_MB';E={[math]::Round($_.WriteTransferCount/1MB,2)}} |
Format-Table -AutoSize

# Plan database migration to new storage
# Step 1: Prepare new SSD volume
# Format with 64KB allocation unit size (optimal for Exchange)

# PowerShell to format (run as admin):
# Format-Volume -DriveLetter S -FileSystem NTFS -AllocationUnitSize 65536 -NewFileSystemLabel "ExchangeDB"-DriveLetter S -FileSystem NTFS -AllocationUnitSize 65536 -NewFileSystemLabel "ExchangeDB"

# Step 2: Create folder structure on new volume
$newDbPath = "S:ExchangeDatabases"
$newLogPath = "S:ExchangeLogs"  # Or separate volume L: for logs

New-Item -Path $newDbPath -ItemType Directory -Force
New-Item -Path $newLogPath -ItemType Directory -Force

# Step 3: Move databases to new storage (one at a time)
# This dismounts the database briefly
$db = "Mailbox Database 01"
$newEdbPath = "$newDbPath$db$db.edb"$db$db.edb"
$newLogFolder = "$newLogPath$db"$db"

# Create database-specific folders
New-Item -Path "$newDbPath$db"$db" -ItemType Directory -Force
New-Item -Path $newLogFolder -ItemType Directory -Force

# Move database (causes brief outage for that database)
Move-DatabasePath -Identity $db -EdbFilePath $newEdbPath -LogFolderPath $newLogFolder -Confirm:$false

# Step 4: Verify new location
Get-MailboxDatabase $db | Select-Object Name, EdbFilePath, LogFolderPath | Format-List

# Step 5: Monitor performance after migration
Get-Counter "\$env:COMPUTERNAMEMSExchange Database ==> Instances($db)I/O Database Reads (Attached) Average Latency"$db)I/O Database Reads (Attached) Average Latency" |
    Select-Object -ExpandProperty CounterSamples

# Generate list of paths that must be excluded from AV
$ExInstall = (Get-ItemProperty 'HKLM:SOFTWAREMicrosoftExchangeServer15Setup').MsiInstallPath

Write-Host "=== Folder Exclusions ===" -ForegroundColor Yellow

# Exchange installation folder
Write-Host $ExInstall

# Database and log folders
Get-MailboxDatabase | ForEach-Object {
    Write-Host $_.EdbFilePath.PathName
    Write-Host $_.LogFolderPath.PathName
}

# Content index folders (in same location as databases)
Get-MailboxDatabase | ForEach-Object {
    $ciPath = Join-Path (Split-Path $_.EdbFilePath.PathName) "*.Single"
    Write-Host $ciPath
}

# Cluster folder (if DAG)
Write-Host "C:WindowsCluster"

Write-Host "`n=== File Extension Exclusions ===" -ForegroundColor Yellow
Write-Host "*.edb - Database files"
Write-Host "*.log - Transaction logs"
Write-Host "*.chk - Checkpoint files"
Write-Host "*.jrs - Reserved logs"
Write-Host "*.que - Queue database"
Write-Host "*.txt - Message tracking logs"

Write-Host "`n=== Process Exclusions ===" -ForegroundColor Yellow
Write-Host "$ExInstallBinEdgeTransport.exe"
Write-Host "$ExInstallBinMicrosoft.Exchange.Store.Worker.exe"
Write-Host "$ExInstallBinMSExchangeDelivery.exe"
Write-Host "$ExInstallBinMSExchangeSubmission.exe"
Write-Host "$ExInstallFIP-FSBinms.exe"-FSBinms.exe"

# Current configuration
Get-MailboxDatabase | Select-Object Name,
    @{N='DbVolume';E={(Split-Path $_.EdbFilePath.PathName).Substring(0,2)}},
    @{N='LogVolume';E={(Split-Path $_.LogFolderPath.PathName).Substring(0,2)}} |
Format-Table -AutoSize

# If databases and logs are on same volume, separate them:

# Step 1: Prepare dedicated log volume (format with 64KB allocation)
# D: = Database volume
# L: = Log volume

# Step 2: Move log files to dedicated volume
$databases = Get-MailboxDatabase

foreach ($db in $databases) {
    $dbName = $db.Name
    $newLogPath = "L:ExchangeLogs$dbName"

    # Create folder
    New-Item -Path $newLogPath -ItemType Directory -Force

    # Move logs (requires brief database dismount)
    Write-Host "Moving logs for $dbName to $newLogPath"$newLogPath" -ForegroundColor Cyan
    Move-DatabasePath -Identity $dbName -LogFolderPath $newLogPath -ConfigurationOnly -Confirm:$false

    # Copy existing logs manually, then mount
    # Alternatively, let Exchange create new logs after move
}

# Verify separation
Get-MailboxDatabase | Select-Object Name,
    @{N='DbPath';E={$_.EdbFilePath.PathName}},
    @{N='LogPath';E={$_.LogFolderPath.PathName}} |
Format-Table -AutoSize

# Check current disk configuration
Get-Disk | Select-Object Number, FriendlyName, Size, PartitionStyle, OperationalStatus |
    Format-Table -AutoSize

Get-Partition | Where-Object {$_.DriveLetter} |
    Select-Object DiskNumber, DriveLetter, Size, Type | Format-Table -AutoSize

# Check allocation unit size (should be 64KB for Exchange volumes)
Get-Volume | Where-Object {$_.DriveLetter} | ForEach-Object {
    $vol = $_
    $fsutil = fsutil fsinfo ntfsinfo "$($_.DriveLetter):"
    $bytesPerCluster = ($fsutil | Select-String "Bytes Per Cluster").ToString().Split(":")[1].Trim()
    [PSCustomObject]@{
        Drive = $_.DriveLetter
        Label = $_.FileSystemLabel
        AllocationUnit = $bytesPerCluster
    }
} | Format-Table -AutoSize

# Storage optimization checklist:
Write-Host "`n=== Storage Best Practices Checklist ===" -ForegroundColor Yellow
Write-Host "[ ] RAID-10 for databases (not RAID-5)"-5)"
Write-Host "[ ] 64KB allocation unit size"
Write-Host "[ ] Write caching enabled with BBU"
Write-Host "[ ] HBA queue depth optimized (32-64)"-64)"
Write-Host "[ ] Multipath I/O configured (for SAN)"
Write-Host "[ ] Storage firmware up to date"
Write-Host "[ ] No disk hot spares in degraded state"
Write-Host "[ ] ReFS considered for larger deployments"