Amidst the ongoing discourse on the trajectory of Bcachefs within the Linux kernel's mainline, an intriguing detail regarding the Btrfs file system emerged. Meta (formerly Facebook) has been a prominent adopter of Btrfs for an extended period. The company boasts a significant team of engineers dedicated to the Btrfs file system, renowned for its extensive use in production environments over many years. Introduced by Oracle in 2007, Btrfs stands as an advanced copy-on-write file system that offers capabilities such as snapshots, data compression, online scaling, and checksums. These features render it ideal for managing large-capacity storage and scenarios demanding high data security. Meta's utilization of Btrfs underscores the system's practical value in large-scale, demanding environments, leading to cost savings amounting to billions of dollars in infrastructure expenses.