Amid the ongoing discussion over [1]what will happen too Bcachefs in the mainline Linux kernel , an interesting anecdote around Btrfs was mentioned.

Meta (Facebook) has long been one of the most prominent users of the Btrfs file-system. Meta employs a number of engineers working on the Btrfs file-system and for years have long been known to use it in production. That's not knew and there have been presentations in the past such as how Meta depends upon Btrfs for their "entire infrastructure":

Josef Bacik, a prominent Btrfs engineer at Meta, wrote about the magnitude of impact for Meta's Btrfs usage:

"The Meta infrastructure is built completely on btrfs and its features. We have saved billions of dollars in infrastructure costs with the features and robustness of btrfs."

With the scale to which Meta operates and their massive infrastructure, Btrfs is attributed as having saved "billions of dollars" thanks to its advanced feature set and robustness. An interesting anecdote for those that continue to question Btrfs or its suitability for use in production environments.

More commentary can be found via [2]this LKML thread amid the ongoing discussion over Bcachefs in the mainline Linux kernel.



[1] https://www.phoronix.com/news/Bcachefs-Linux-6.18-Waits

[2] https://lore.kernel.org/lkml/20250809192156.GA1411279@fedora/