- Facebook are using container for almost all their services to make them as mobile as they can.
- DBs (Mysql) are the exception here. They are deployed the tradional way.
- Facebook uses Btrfs for their build systems (uses snapshots).
- They use Btrfs for Devvms which are VMs containing the whole Facebook website and the tools required to work on it (HHVM, build tools …). Btrfs Compression helps them ship more VMs per Disk (Flash cards).
- Btrfs has a histori problem with “not enough space”.
- Btrfs will be used for offline messages in Whatsapp.
- This is still experimental, and scalability problems are still poping up.
- The main usecase for Btrfs at Facebook is for their shared container pool. They use Btrfs as the main FS for their containers.
What I learned really is that Btrfs is stable enough and it kind of solves some problems compared to other FS e.g. Write amplification on SSDs is reduced by compression.