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A refined, consistent, and practice-focused guide for running Btrfs efficiently on your at1 server. The structure emphasizes clarity, reliability, and long-term maintainability.

1. Overview

Btrfs is a modern copy-on-write filesystem designed for environments where integrity, snapshots, and flexibility are essential. It excels with:

  • frequent small writes,
  • container storage,
  • snapshot-heavy workflows, and
  • large multi-device volumes.

With correct mount options and regular maintenance, Btrfs provides excellent performance and data safety for NVMe+HDD or SSD-based RAID setups.

2. Recommended Mount Options

Optimized for SSD-RAID, fast metadata handling, and balanced compression:

  • noatime – avoids unnecessary writes.
  • ssd, ssd_spread – enables SSD optimization.
  • compress=zstd:3 – modern, efficient compression.
  • space_cache=v2 – improved metadata caching.
  • autodefrag – reduces fragmentation on small-write workloads.
  • commit=120 – reduces sync/write bursts.
  • subvol=@ – clean separation of root data.

Example: /etc/fstab

UUID=48a6a5b9-eca7-4268-8dc1-8ef10f5d5eaf   /mnt/raid1  btrfs   noatime,ssd,ssd_spread,compress=zstd:3,space_cache=v2,autodefrag,commit=120,subvol=@   0  0

3. Maintenance & Upkeep

Regular care ensures long-term performance and integrity.

3.1 Scrub

Checksums are validated, and redundancy repairs corrupted blocks automatically.

Install:

apt-get install btrfsmaintenance

Enable timer:

systemctl enable --now btrfs-scrub.timer

Start scrub manually:

btrfs scrub start /mnt/raid1

View scrub status:

btrfs scrub status /mnt/raid1

3.2 Balance (only occasionally needed)

Useful when metadata or data chunks become unevenly distributed:

btrfs balance start -dusage=75 /mnt/raid1

3.3 Defragment

Helpful for workloads with many fragmented small files:

btrfs filesystem defrag -r /mnt/raid1

3.4 Trim for SSDs

Recommended for SSDs to maintain performance:

systemctl enable --now fstrim.timer

4. Performance Optimizations

Fine-tuning options to reduce write amplification and improve responsiveness.

4.1 Incus Containers

Avoid CoW on logs:

chattr +C /var/log/incus

4.2 Browser Caches

chattr +C ~/.cache

4.3 Java Services (e.g., Jitsi)

chattr +C /var/log/jitsi

4.4 Dirty Page Limits

Lower latency by controlling write cache size:

vm.dirty_background_bytes = 52428800
vm.dirty_bytes = 209715200

4.5 Large Files & Projects

Disable CoW where large sequential writes dominate:

chattr +C /mnt/raid1/PROJECTS

Your Btrfs environment is now structured, efficient, and well-aligned with long-term reliability.