# Event ID 4113 Example
Log Name:      Application
Source:        MSExchangeRepl
Event ID:      4113
Level:         Error
Description:
The copy of database 'MailboxDB01' on this server is
failing. Error: The log file could not be copied to
the passive node. The Microsoft Exchange Replication
service will attempt to recover this copy.

Copy Status: Failed
Copy Queue Length: 15842
Replay Queue Length: 0

# Quick status check
Get-MailboxDatabaseCopyStatus * | Where-Object { $_.Status -ne "Mounted" -and $_.Status -ne "Healthy" } | Format-Table Name, Status, CopyQueueLength, ReplayQueueLength, ContentIndexState -AutoSize

# Detailed status for specific database
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01" | Format-List

# Get status of all database copies
Get-MailboxDatabaseCopyStatus * | Format-Table Name, Status, CopyQueueLength, ReplayQueueLength, LastInspectedLogTime, ContentIndexState -AutoSize

# Check for suspended copies
Get-MailboxDatabaseCopyStatus * | Where-Object { $_.Status -like "*Suspended*" }

# Get detailed error information
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2" | Format-List *Error*

# Test replication health
Test-ReplicationHealth | Format-Table Server, Check, Result, Error -AutoSize

# Check DAG network configuration
Get-DatabaseAvailabilityGroupNetwork | Format-List Name, Subnets, ReplicationEnabled

# Verify replication service
Get-Service MSExchangeRepl | Select-Object Name, Status, StartType

# Check disk space on passive server
Get-WmiObject Win32_LogicalDisk | Where-Object { $_.DriveType -eq 3 } | Select-Object DeviceID, @{N='FreeGB';E={[math]::Round($_.FreeSpace/1GB,2)}}, @{N='TotalGB';E={[math]::Round($_.Size/1GB,2)}}

# Check log file status
$db = Get-MailboxDatabase -Identity "MailboxDB01"
$logPath = $db.LogFolderPath
Get-ChildItem $logPath -Filter "*.log" | Measure-Object | Select-Object Count

# Check for log generation gap
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01" | Select-Object Name, LastLogGenerated, LastLogCopied, LastLogReplayed

# If copy is suspended, resume it
Resume-MailboxDatabaseCopy -Identity "MailboxDB01\Server2"

# Wait and check status
Start-Sleep -Seconds 30
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2" | Format-List Status, CopyQueueLength, LastInspectedLogTime

# If status is still failed, restart replication service
Restart-Service MSExchangeRepl -Force

# Re-check status
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2"

# Test connectivity between DAG members
$dagMembers = (Get-DatabaseAvailabilityGroup).Servers
foreach ($member in $dagMembers) {
    Write-Host "Testing connectivity to $member..."
    Test-NetConnection -ComputerName $member -Port 64327  # Replication port
}

# Check replication network
Get-DatabaseAvailabilityGroupNetwork | Format-List

# If replication network is misconfigured, fix it
Set-DatabaseAvailabilityGroupNetwork -Identity "DAG01\ReplicationNetwork" -ReplicationEnabled $true -IgnoreNetwork $false

# Verify Windows Firewall rules
Get-NetFirewallRule -DisplayName "*Exchange*" | Where-Object { $_.Enabled -eq $true } | Select-Object DisplayName, Direction, Action

# Check what's consuming space
Get-ChildItem -Path "D:\ExchangeDatabases" -Recurse | Group-Object Extension | Sort-Object { ($_.Group | Measure-Object Length -Sum).Sum } -Descending | Select-Object Name, Count, @{N='SizeGB';E={[math]::Round(($_.Group | Measure-Object Length -Sum).Sum/1GB,2)}}

# Truncate logs after successful backup
# (Backup software should do this automatically)

# If logs are accumulating, verify backup is completing
Get-MailboxDatabase | Select-Object Name, LastFullBackup, LastIncrementalBackup

# Move database to larger volume if needed
Move-DatabasePath -Identity "MailboxDB01" -EdbFilePath "E:\Databases\MailboxDB01.edb" -LogFolderPath "E:\Databases\MailboxDB01_Logs"

# First, suspend the copy
Suspend-MailboxDatabaseCopy -Identity "MailboxDB01\Server2" -Confirm:$false

# Delete existing database and log files (be careful!)
$copyStatus = Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2"
Write-Host "Database path: $($copyStatus.DatabasePathFile)"
Write-Host "Log path: $($copyStatus.LogFolderPath)"
Write-Host ""
Write-Host "WARNING: About to delete database copy files. Press Enter to continue..."
Read-Host

# Remove old files
Remove-Item -Path $copyStatus.DatabasePathFile -Force
Remove-Item -Path "$($copyStatus.LogFolderPath)\*" -Force

# Reseed the database copy
Update-MailboxDatabaseCopy -Identity "MailboxDB01\Server2" -DeleteExistingFiles

# Monitor reseed progress
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2" | Format-List Status, CopyQueueLength, ReplayQueueLength, SeedingPercent

# Check content index state
Get-MailboxDatabaseCopyStatus * | Select-Object Name, ContentIndexState, ContentIndexErrorMessage

# If content index is failed, rebuild it
Update-MailboxDatabaseCopy -Identity "MailboxDB01\Server2" -CatalogOnly

# Monitor rebuild progress
Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2" | Select-Object Name, ContentIndexState

# Alternative: Reseed just the catalog from another healthy copy
Update-MailboxDatabaseCopy -Identity "MailboxDB01\Server2" -CatalogOnly -SourceServer Server1

# Check all database copy status
Get-MailboxDatabaseCopyStatus * | Format-Table Name, Status, CopyQueueLength, ReplayQueueLength, ContentIndexState -AutoSize

# Verify copy queue is draining
$start = (Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2").CopyQueueLength
Start-Sleep -Seconds 60
$end = (Get-MailboxDatabaseCopyStatus -Identity "MailboxDB01\Server2").CopyQueueLength
Write-Host "Copy queue changed from $start to $end"$end"

# Run replication health test
Test-ReplicationHealth | Where-Object { $_.Result -ne "Passed" }

# Verify no more 4113 events
Get-EventLog -LogName Application -Source MSExchangeRepl -EntryType Error -Newest 20 | Where-Object { $_.EventID -eq 4113 }