Introduction to BTRFS

1. BTRFS
Spread some butter
on your disk
Rangel Ivanov
rangelivanov@embedlynx.com
https://github.com/ironsteel

2. Agenda
• BTRFS in a nutshell
• Защо BTRFS?
• Възможности
• Реализация (CoW, B-tree)
• Демонстрация и въпроси

3. BTRFS in a nutshell
• Chris Mason, Oracle 2007
• Marked as production ready - 2012
• Modified B-tree sturcture
• Copy on Write
• Snapshots, pooling, checksums
• Some distros shipping BTRFS as default
• > Linux 3.18

4. Защо BTRFS?
• ZFS
• Проблемен лиценз (CDDL)
• Трудна интеграция
• Не използва memory инфраструктурата на linux
• Не преизползва RAID кода в linux
• Липсва deduplication
• LVM
• Проблематични/бавни snapshots

5. Възможности
● Subvolumes, quotas
● Online resize
● Snapshots
● Checksums on data
● SSD aware
● Compression
● Incremental backup, send/receive
● Background online scrub
● Conversion from ext3/ext4
● raid0, raid1, raid10, raid5, raid6

6. Реализация
● Copy on Write
● New block put next to existing one(copy)
● Metadata chages
● Deduplication
● B-tree data structure
● Fast search, indexing
● Fast insertion/deletion of nodes
● Rebalance

7. Demo
● Creating a subvolume
● ‘btrfs subvolume create /home/user/subvol’
● Resizing a subvolume
● ‘btrfs filesystem resize +[-]2G /home/user/subvol’
● Scrub/defrag
● ‘btrfs scrub [device]’
● Snapshot
● ‘btrfs subvolume snapshot [src] [dest]’
● Send/Receive

8. THE END
БЛАГОДАРЯ ВИ ЗА ВНИМАНИЕТО