Overview

Daemon Mode runs continuously on client machines, automatically backing up devices according to a schedule. Configuration is managed via a YAML file at /etc/xreplicator/agent.yaml (Linux) or C:\ProgramData\xreplicator\agent.yaml (Windows).

Starting the Daemon

# Start the daemon
sudo systemctl start backup-agent
 
# Enable automatic startup on boot
sudo systemctl enable backup-agent
 
# Check status
sudo systemctl status backup-agent
 
# View logs
sudo journalctl -u backup-agent -f

# Windows (run as Administrator)
Start-Service XReplicatorAgent
Get-Service XReplicatorAgent

Configuration File

Edit the config file, then restart the service to apply changes:

sudo nano /etc/xreplicator/agent.yaml
sudo systemctl restart backup-agent

# Windows
notepad C:\ProgramData\xreplicator\agent.yaml
Restart-Service XReplicatorAgent

Example Agent Configs

• Linux: /docs/configuration/agent-config-linux
• Windows: /docs/configuration/agent-config-windows

Device Configuration

device.path (string, required)

Path to the block device or file to back up.

device:
  path: "/dev/vdb"

device.paths (array, optional)

Use this instead of device.path when backing up multiple devices.

device:
  paths:
    - "/dev/vdb"
    - "/dev/vdc"

device.sync_wait_ms (integer, default: 500)

Wait time in milliseconds after filesystem sync before backup. Ensures buffered writes are committed to disk.

Storage Configuration

storage.type (string, required)

Storage backend type. Options: "local" or "grpc".

storage.path (string, required if type is "local")

Local directory for the repository. Created automatically if it doesn’t exist.

storage:
  type: "local"
  path: "/var/lib/backup/repo"

gRPC Storage Options

TLS Options

Change Tracking

XReplicator can use optimized Linux change tracking where supported so incremental backup cycles follow the amount of changed data. If optimized tracking is unavailable, the agent falls back to a safe scan-based path.

Advanced tracking parameters are intentionally not documented publicly. Keep the default settings unless XMigrate support recommends a change for your environment.

Backup Schedule

Full Backups

Incremental Backups

Application-Aware Tracking

app_aware_tracking:
  enabled: true

Retention Policy

Pipeline Configuration

Tuning for Larger Disks (Best Practices)

For larger disks, tune for the outcome you want:

• Lower memory pressure and fewer stalls: reduce batch_size and workers
• Higher throughput on capable hosts: increase workers gradually and monitor CPU, memory, disk, and network saturation

Rules to keep configurations safe

• Keep fixed_block_size_mb the same on agent and server.
• Start conservative, then scale up one setting at a time.
• Change one setting per test window so regressions are easy to isolate.

Recommended profiles

Profile A: Large disks, balanced (recommended starting point)

daemon:
  pipeline:
    fixed_block_size_mb: 16
    batch_size: 100
    workers: 4

Profile B: Large disks on memory-constrained hosts

daemon:
  pipeline:
    fixed_block_size_mb: 8
    batch_size: 25
    workers: 1
    max_io_queue_depth: 2
    channel_buffer_mult: 1
    max_pipeline_memory_mb: 256

Profile C: High-throughput hosts (more CPU and RAM)

daemon:
  pipeline:
    fixed_block_size_mb: 16
    batch_size: 200
    workers: 6

Troubleshooting guidance

If agent memory grows rapidly or backups appear stuck:

• Reduce batch_size first (for example, 200 -> 100 -> 25).
• Reduce workers next (for example, 4 -> 2 -> 1).
• Keep pipeline settings stable while troubleshooting.

Compression

Logging

Configuration Examples

Local Storage

storage:
  type: "local"
  path: "/var/lib/backup/repo"

gRPC with TLS (Production)

storage:
  type: "grpc"
  grpc:
    server_address: "backup.prod.example.com:50051"
    timeout: 10m
    max_retries: 5
    tls:
      enabled: true
      cert_file: "/etc/backup/tls/client.crt"
      key_file: "/etc/backup/tls/client.key"
      ca_file: "/etc/backup/tls/ca.crt"

Daily Full Backups (Database Server)

schedule:
  full_backup:
    enabled: true
    frequency: "daily"
    time: "03:00"
    max_age_days: 7
  incremental_backup:
    enabled: true
    frequency: "custom"
    interval: 15m

High Bandwidth (1 Gbps+)

daemon:
  pipeline:
    batch_size: 400
    workers: 8
  compression:
    enabled: true
    level: 1

Low Bandwidth (10 Mbps)

daemon:
  pipeline:
    batch_size: 20
    workers: 2
  compression:
    enabled: true
    level: 3

Memory-Constrained (1 GB Limit)

daemon:
  pipeline:
    max_io_queue_depth: 3
    channel_buffer_mult: 2
    max_pipeline_memory_mb: 1024
    workers: 2
    fixed_block_size_mb: 8
  compression:
    enabled: true
    level: 1