5 ms·

Is btrfs still super slow at deleting large files? It can take multiple seconds (like 5-10) on my fileserver to delete just one ~10GB file.

• cmurf 6y ago
  The 'rm' command should complete pretty quickly. Actually freeing up space takes time since a delete is subject to delayed allocation. The default transaction commit time is 30 seconds. And if there are snapshots or reflink copies, a backref walk is needed before extents can be freed.
  • knorker 6y ago
    I'm talking about the time it takes for the `rm` command to finish. I've started the habit of running all `rm` commands in the background on btrfs.
    • cmurf 6y ago
      If it's reproducible, my suggestion is to strace the rm command and find out what it's doing that's taking so long; and post it to the mailing list: https://btrfs.wiki.kernel.org/index.php/Btrfs_mailing_list https://btrfs.wiki.kernel.org/index.php/Btrfs_mailing_list
      • WGH_ 6y ago
        Recording the kernel profile with perf would be more useful, I think. strace would probably only show long "unlink" syscall.
        • cmurf 6y ago
          Yeah, and if perf is unrevealing, sysrq+t.
• throwme45353464 6y ago
  Do you have snapshots enabled by any chance, or any other btrfs features?
  • knorker 6y ago
    I'm not aware of using any features. Where should I check this?
• ac29 6y ago
  I tested removing a 10GiB file of random data from a btrfs filesystem, it took 254ms.