Rafael Pfister

Services & logs

Control services, follow logs, count error codes, check disk and load.

Service status

Shows state, start type and dependencies of a service.

PowerShell (Windows)

Get-Service Built-in 

Get-Service postfix | Format-List Name, Status, StartType, DependentServices

sc.exe Built-in 

sc.exe qc postfix
sc.exe queryex postfix

Unix shell (bash)

systemctl Built-in 

systemctl status postfix --no-pager
systemctl is-enabled postfix

service Add-on tool 

service postfix status

Restart a service

Restarts a service and shows its state afterwards.

PowerShell (Windows)

Restart-Service Built-in 

Restart-Service postfix -Force
Get-Service postfix | Select-Object Name, Status

sc.exe Built-in 

sc.exe stop postfix
sc.exe start postfix

Unix shell (bash)

systemctl Built-in 

sudo systemctl restart postfix
systemctl status postfix --no-pager | head -10

service Add-on tool 

sudo service postfix restart

Interrupts running connections. On a mail server that means submissions are rejected for a few seconds and retried later.

Follow a log

Follows a log file or the service journal live while you reproduce a fault.

Postfix

PowerShell (Windows)

Get-Content -Wait Built-in 

Get-Content "/var/log/mail.log" -Tail 50 -Wait

Get-WinEvent Built-in 

Get-WinEvent -LogName Application -MaxEvents 50 | Where-Object { $_.ProviderName -like "*postfix*" } | Format-Table TimeCreated, Id, LevelDisplayName, Message -AutoSize

Unix shell (bash)

journalctl Built-in 

journalctl -u postfix -f -n 50

tail Built-in 

tail -f -n 50 /var/log/mail.log

Search a log

Searches a term or response code in a log file and shows the last matches.

PowerShell (Windows)

Select-String Built-in 

Select-String -Path "/var/log/mail.log" -Pattern "550" | Select-Object -Last 40

Get-WinEvent Built-in 

Get-WinEvent -FilterHashtable @{LogName="Application"; Level=2; StartTime=(Get-Date).AddHours(-24)} | Format-Table TimeCreated, ProviderName, Message -AutoSize

Unix shell (bash)

grep Built-in 

grep -i "550" /var/log/mail.log | tail -40

journalctl Add-on tool 

journalctl --since "24 hours ago" | grep -i "550" | tail -40

Count SMTP error codes

Counts the 4xx and 5xx response codes in the mail log, sorted by frequency: shows immediately whether one destination or a pattern is at fault.

Mail-Log

PowerShell (Windows)

Select-String Built-in 

Select-String -Path "/var/log/mail.log" -Pattern "\b(4\d\d|5\d\d)\b" |
  Group-Object { ($_.Line -split "\s+" | Select-String "^[45]\d\d$").Matches.Value } -NoElement |
  Sort-Object Count -Descending | Select-Object -First 15

Get-MessageTrackingLog Add-on tool 

Get-MessageTrackingLog -EventId FAIL -Start (Get-Date).AddHours(-24) | Group-Object RecipientStatus -NoElement | Sort-Object Count -Descending

Unix shell (bash)

grep / awk Built-in 

grep -oE "\b[45][0-9][0-9] [0-9]\.[0-9]\.[0-9]" /var/log/mail.log | sort | uniq -c | sort -rn | head -15

journalctl Add-on tool 

journalctl -u postfix --since today | grep -oE "status=(bounced|deferred|sent)" | sort | uniq -c

Disk space

Shows free space and the largest directories: a full disk stops the queue and the logs.

PowerShell (Windows)

Get-PSDrive / Get-Volume Built-in 

Get-Volume | Where-Object DriveLetter | Format-Table DriveLetter, FileSystemLabel, @{N="Frei(GB)";E={[math]::Round($_.SizeRemaining/1GB,1)}}, @{N="Gesamt(GB)";E={[math]::Round($_.Size/1GB,1)}}

Get-ChildItem Built-in 

Get-ChildItem C:\ -Recurse -File -ErrorAction SilentlyContinue | Sort-Object Length -Descending | Select-Object -First 10 FullName, @{N="MB";E={[math]::Round($_.Length/1MB,1)}}

Unix shell (bash)

df / du Built-in 

df -h
du -xh --max-depth=1 /var | sort -h | tail -15

ncdu Add-on tool 

ncdu /var

Load and processes

Shows the processes with the highest CPU load and their memory use.

PowerShell (Windows)

Get-Process Built-in 

Get-Process | Sort-Object CPU -Descending | Select-Object -First 10 Name, Id, CPU, @{N="MB";E={[math]::Round($_.WorkingSet64/1MB)}}

Get-Counter Built-in 

Get-Counter "\Processor(_Total)\% Processor Time", "\Memory\Available MBytes" -SampleInterval 2 -MaxSamples 3

Unix shell (bash)

ps / top Built-in 

ps aux --sort=-%cpu | head -11
top -b -n 1 | head -15

htop Add-on tool 

htop -d 10

Other areas