Redundant database

This guide covers methods for replicating, synchronizing, and migrating the VoIPmonitor CDR database between instances.

Overview

VoIPmonitor offers the following methods for CDR synchronization:

Method	Description	Use Case
Database Backup Mode	Dedicated sniffer reads from source DB, writes to destination DB	Online migration, read-only replicas, hot-standby
Master-Master Replication	Bidirectional MySQL/MariaDB replication	Full HA with automatic failover (see Master-Master Replication)

ℹ️ Note: Both methods synchronize CDR data only. GUI settings (users, alerts, capture rules) must be migrated separately via Tools → Backup & Restore.

Database Backup Mode

A dedicated VoIPmonitor instance reads CDRs from a source database and writes them to a destination database. This is the recommended method for online GUI migration.

Architecture

Online GUI Migration Workflow

Install VoIPmonitor GUI on the new server with a fresh database
Backup configuration: On old GUI → Tools → Backup & Restore → backup configuration tables
Restore configuration: On new GUI → upload the backup file (do this BEFORE starting migration)
Create migration config file (see below)
Start migration instance
Once replication catches up, switch users to the new GUI
Stop migration instance and decommission old server

Configuration

Copy the original config and modify for migration mode:

scp root@old-server:/etc/voipmonitor.conf /etc/voipmonitor-migrate.conf

Required modifications in /etc/voipmonitor-migrate.conf:

# 1. Avoid port conflict with production sniffer
managerport = 5030

# 2. DISABLE packet capture (comment out all interface lines)
# interface = eth0

# 3. Destination Database (NEW server - local)
mysqlhost      = 127.0.0.1
mysqldb        = voipmonitor
mysqlusername  = root
mysqlpassword  = new_password

# 4. Source Database (OLD server - remote)
database_backup_from_mysqlhost     = 192.168.0.1
database_backup_from_mysqldb       = voipmonitor
database_backup_from_mysqlusername = root
database_backup_from_mysqlpassword = old_password

# 5. Start date for replication
database_backup_from_date = 2024-01-01

# 6. Performance tuning
database_backup_insert_threads = 3   # Higher = faster but more load
database_backup_pause          = 3   # Higher = less load on source DB

Parameter Reference:

Parameter	Description
`database_backup_from_date`	Start date for sync (YYYY-MM-DD)
`database_backup_insert_threads`	Parallel write threads (higher = faster, more load)
`database_backup_pause`	Seconds between batches (higher = gentler on source DB)
`database_backup_desc_dir`	Set `yes` to also write new incoming data to destination

Running the Migration

Test manually first:

voipmonitor --config-file /etc/voipmonitor-migrate.conf -k -v 1

Run as systemd service:

Create /etc/systemd/system/voipmonitor-migrate.service:

[Unit]
Description=VoIPmonitor Database Migration
After=network.target mysql.service

[Service]
Type=simple
ExecStart=/usr/local/sbin/voipmonitor -c /etc/voipmonitor-migrate.conf
Restart=on-failure

[Install]
WantedBy=multi-user.target

systemctl daemon-reload
systemctl enable --now voipmonitor-migrate

Migrating PCAP Files

Database migration does NOT include PCAP files. Migrate separately using rsync:

rsync -avz root@old-server:/var/spool/voipmonitor/ /var/spool/voipmonitor/

⚠️ Warning: Timezone must match between servers. PCAP paths use local timezone (spooldir/YYYY-MM-DD/HH/MM/). Mismatched timezones cause GUI to fail finding historical PCAPs.

# Check timezone
timedatectl

# Set timezone
timedatectl set-timezone Europe/Prague

Schema Compatibility

The migration instance automatically handles database schema upgrades. This is useful when:

Migrating to different MySQL/MariaDB versions
Upgrading VoIPmonitor versions during migration
Moving from local MySQL to remote Percona

To identify schema changes manually:

systemctl restart voipmonitor
tail -f /var/log/voipmonitor/voipmonitor.log | grep -E "CLI|ALTER|CREATE TABLE"

⚠️ Warning: For cross-version migration (e.g., MySQL 5.7 to 8.0), use the migration instance method instead of mysqldump. It handles schema differences automatically.