btrfs_metadata.md 2.6 KB
Understand the alert
The btrfs_metadata alert calculates the percentage of used Btrfs metadata space for a Btrfs filesystem. If you receive this alert, it indicates that your Btrfs filesystem's metadata space is being utilized at a high rate.
Troubleshoot the alert
Warning: Data is valuable. Before performing any actions, make sure to take necessary backup steps. Netdata is not responsible for any loss or corruption of data, database, or software.
Add more physical space
Determine which disk you want to add and in which path:
root@netdata~ # btrfs device add -f /dev/<new_disk> <path>If you get an error that the drive is already mounted, you might have to unmount:
root@netdata~ # btrfs device add -f /dev/<new_disk> <path>Check the newly added disk:
root@netdata~ # btrfs filesystem showBalance the system to make use of the new drive:
root@netdata~ # btrfs filesystem balance <path>
Delete snapshots
List the snapshots for a specific path:
root@netdata~ # sudo btrfs subvolume list -s <path>Delete an unnecessary snapshot:
root@netdata~ # btrfs subvolume delete <path>/@some_dir-snapshot-test
Enable a compression mechanism
Apply compression to existing files by modifying the fstab configuration file (or during the mount procedure) with the compress=alg option. Replace alg with zlib, lzo, zstd, or no (for no compression). For example, to re-compress the /mount/point path with zstd compression:
root@netdata # btrfs filesystem defragment -r -v -czstd /mount/point
- Enable a deduplication mechanism
Deduplication tools like duperemove, bees, and dduper can help identify blocks of data sharing common sequences and combine extents via copy-on-write semantics. Ensure you check the status of these 3rd party tools before using them.
- Perform a balance
Balance data/metadata/system-data in empty or near-empty chunks for Btrfs filesystems with multiple disks, allowing space to be reassigned:
root@netdata # btrfs balance start -musage=50 -dusage=10 -susage=5 /mount/point