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diff --git a/src/health/guides/btrfs/btrfs_metadata.md b/src/health/guides/btrfs/btrfs_metadata.md new file mode 100644 index 00000000..6c44ee09 --- /dev/null +++ b/src/health/guides/btrfs/btrfs_metadata.md @@ -0,0 +1,70 @@ +### 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.** + +1. **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 show + ``` + + - Balance the system to make use of the new drive: + ``` + root@netdata~ # btrfs filesystem balance <path> + ``` + +2. **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 + ``` + +3. **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 + ``` + +4. **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. + + - [duperemove](https://github.com/markfasheh/duperemove) + - [bees](https://github.com/Zygo/bees) + - [dduper](https://github.com/lakshmipathi/dduper) + +5. **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 + ``` + +### Useful resources + +1. [The Btrfs filesystem on Arch Linux website](https://wiki.archlinux.org/title/btrfs) +2. [The Btrfs filesystem on kernel.org website](https://btrfs.wiki.kernel.org)
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