Btrfsの構造

1. Btrfs ͷػೳɾಛ௃ BtrfsͬͯͲΜͳϑΝΠϧγεςϜ? 2013-06-14 1 / 51
2. Btrfs ͷػೳɾಛ௃ 2013-06-14 2 / 51
3. Btrfs ͷػೳɾಛ௃ . . Copy On Write 2013-06-14 3 / 51
4. Btrfs ͷػೳɾಛ௃ . . Journal 2013-06-14 4 / 51
5. Btrfs ͷػೳɾಛ௃ 2013-06-14 5 / 51
6. Btrfs ͷػೳɾಛ௃ 2013-06-14 6 / 51
7. Btrfs ͷػೳɾಛ௃ . . Journal ͷऑ఺ ʮδϟʔφϧʯͱʮຊମʯͱೋճॻ͔ͳ͚Ε͹͍͚ͳ͍ σʔλ΋δϟʔφϧԽ͢Δͷ͸ޮ཰͕ѱ͍ ϝλσʔλͳΒ͍͚Δ 2013-06-14 7 / 51
8. Btrfs ͷػೳɾಛ௃ 2013-06-14 8 / 51
9. Btrfs ͷػೳɾಛ௃ . . Copy On Write Ұճ͔͠ॻ͔ͳ͍͍ͯ͘ σʔλɾϝλσʔλ྆ํͷ੔߹ੑΛอͭͷʹ࢖͑Δ 2013-06-14 9 / 51
10. Btrfs ͷػೳɾಛ௃ . . εφοϓγϣ οτ 2013-06-14 10 / 51
11. Btrfs ͷػೳɾಛ௃ . . σϑϥά 2013-06-14 11 / 51
12. Btrfs ͷػೳɾಛ௃ . . Quota QGroup ͱݺ͹ΕΔಛघͳ quota εφοϓγϣ οτ͕͋ΔͷͰʮڞ༗σʔλʯ͕ଘࡏ͢Δ ʮશମͷαΠζʯͱʮڞ༗͞Ε͍ͯͳ͍αΠζʯʹΑΔ੍ݶ͕Ͱ͖Δ ڈ೥ͷ Software Design10 ݄߸ʹࡌͬͯ·͢ 2013-06-14 12 / 51
13. Btrfs ͷػೳɾಛ௃ . . Ext2/3 ͔Βͷ convert ext2/3 ͷσʔλ͕ͦͷ··ม׵Ͱ͖·͢ ؾʹ͍Βͳ͚Ε͹ݩʹ໭ͤ·͢ 2013-06-14 13 / 51
14. Btrfs ͷػೳɾಛ௃ . . ͦͷଞ 16EiB ·Ͱ࢖͑Δ (XFS ͷ 2 ഒ!) checksum ͕͋Δ͔ΒϒϩοΫͷ੔߹ੑνΣ οΫ OK! ಁաతѹॖͰ༰ྔઅ໿! RAID Ͱ৴པੑ޲্! send/receive Ͱޮ཰తͳόοΫΞοϓ! Hot add/remove ͰΒ͘Β͘σΟεΫަ׵! dedup Ͱॏෳഉআ! SSD ༻࠷దԽ΋͋ΔΑ! 2013-06-14 14 / 51
15. Btrfs ͷػೳɾಛ௃ . . কདྷతʹ ॻ͖͜Έͱಉ࣌ʹࣗಈ dedup hot data tracking ͰΑ͘ΞΫηε͢ΔϑΝΠϧΛ SSD ʹΩϟ ογϡ! fsck? 2013-06-14 15 / 51
16. Btrfs ͷػೳɾಛ௃ . . ࢖͍ͨ͘ͳ͖ͬͯͨͰ͠ΐ? 2013-06-14 16 / 51
17. B ໦ . . B ໦ Btrfs ͷ΄ͱΜͲ͍ͨΔͱ͜ΖͰ࢖ΘΕΔσʔλߏ଄ ͜Ε͕Θ͔Βͳ͍ͱ Btrfs ͕Θ͔Βͳ͍ ͳΜͱ͍ͬͯ΋ “BtrFS” = “B-Tree File System” Ͱ͔͢Βͳ! 2013-06-14 17 / 51
18. B ໦ . . ೋ෼୳ࡧ໦ 2013-06-14 18 / 51
19. B ໦ . . B ໦ 2013-06-14 19 / 51
20. B ໦ . . B ໦΁ͷૠೖ 2013-06-14 20 / 51
21. B ໦ . . ෼ׂ 2013-06-14 21 / 51
22. B ໦ . . CoW ૠೖ 2013-06-14 22 / 51
23. B ໦ 2013-06-14 23 / 51
24. B ໦ 2013-06-14 24 / 51
25. B ໦ 2013-06-14 25 / 51
26. B ໦ 2013-06-14 26 / 51
27. B ໦ 2013-06-14 27 / 51
28. B ໦ 2013-06-14 28 / 51
29. Btrfs ͷ໦ . . Btrfs ͷ B ໦ Key ΦϒδΣΫτ ID λΠϓ Φϑηοτ ϊʔυͱϦʔϑ Ұ൪Լ͕Ϧʔϑɺ࢒Γ͕Λϊʔυ ϦʔϑʹΩʔʹରԠ͢Δσʔλ͕อ؅͞ΕΔ 2013-06-14 29 / 51
30. Btrfs ͷ໦ 2013-06-14 30 / 51
31. Btrfs ͷ໦ . . ༷ʑͳ໦ Root tree FS tree extent tree chunk tree device tree CSum tree 2013-06-14 31 / 51
32. Btrfs ͷ໦ . . Root Tree جຊͷ໦! ଞͷ໦ͷ root Λอ࣋ αϒϘϦϡʔϜߏ଄ͷऔಘ 2013-06-14 32 / 51
33. Btrfs ͷ໦ . . FS Tree αϒϘϦϡʔϜɾεφοϓγϣ οτ͝ͱʹ FS tree ͷ root ͕͋Δ σΟϨΫτϦߏ଄ i-node ৘ใ ϑΝΠϧσʔλҐஔ (extent address) 2013-06-14 33 / 51
34. Btrfs ͷ໦ . . chunk ͱ extent 2013-06-14 34 / 51
35. Btrfs ͷ໦ . . device treeɾCSum tree device tree Btrfs ʹొ࿥͞Ε͍ͯΔσόΠεͷ؅ཧ CSum tree 4KB ͝ͱͷ checksum 2013-06-14 35 / 51
36. Btrfs ͷ໦ . . ୳ͯ͠ΈΑ͏ 2013-06-14 36 / 51
37. bootstrap Btrfs ͷ tree ΋ϑΝΠϧ΋શͯ extent address(࿦ཧΞυϨε) ͰΞΫ ηε Root tree ΋ extent address ͰΞΫηε͞ΕΔ chunk tree ࣗ਎΋ Ͳ͏΍ͬͯ࠷ॳͷ extent address Λ෺ཧΞυϨεʹϚοϐϯά͢ Δͷ? 2013-06-14 37 / 51
38. bootstrap . . superblock btrfs Ͱ།Ұ෺ཧతʹΞυϨε͕ܾ·͍ͬͯΔ ύʔςΟγϣϯ ઌ಄͔Β 6410KiB, 6410MiB, 25610GiB, 1PiB root ͷ extent address root tree chunk tree system chunk ͷ chunk ৘ใ chunk tree ͷϊʔυ, Ϧʔϑ͸ system chunk ͔ΒׂΓ౰ͯΒΕΔ 2013-06-14 38 / 51
39. bootstrap . . system chunk 2013-06-14 39 / 51
40. bootstrap 2013-06-14 40 / 51
41. ࠷ۙͷ͜ͱ ࠷ޙʹ͜ͷ 1 ݄͙Β͍;Έ·ͬͯ͘Δ assert ʹ͍ͭͯ࿩͠·͢ 2013-06-14 41 / 51
42. ࠷ۙͷ͜ͱ . . dump [42604.796633] BTRFS assertion failed: !memcmp_extent_buffer( b, &disk_key, offsetof(struct btrfs_leaf, items[0].key), sizeof(disk_key)), file: fs/btrfs/ctree.c, line: 2444 2013-06-14 42 / 51
43. ࠷ۙͷ͜ͱ . . Ωʔ୳ࡧͷ࠷దԽ 2013-06-14 43 / 51
44. ࠷ۙͷ͜ͱ . . snapshot aware defrag 2013-06-14 44 / 51
45. ࠷ۙͷ͜ͱ 2013-06-14 45 / 51
46. ࠷ۙͷ͜ͱ . . tree mod log B-tree ͷมߋ࣌ʹมߋલʹͲ͏͍͏஋͕ೖ͍͔ͬͯͨΛه࿥ transaction ͝ͱʹϦηοτ͞ΕΔ ϝϞϦ্͚ͩͰσΟεΫʹ͸ॻ͔Εͳ͍ ͜ΕͰʮੲͷ B-treeʯΛͱΓ͕ͩͦ͢Ε͕όάͬͯΔ? 2013-06-14 46 / 51
47. ࠷ۙͷ͜ͱ . . ݪҼ͸ʜͳΜͰͩΖ͏? 2013-06-14 47 / 51
48. ࠷ۙͷ͜ͱ ·͋ͱΓ͋͑ͣʮࣗಈσϑϥάʯ੾͓͚ͬͯ͹ (σϑΥϧτ:Φϑ) ͍͍ͱ ࢥ͏Α? 2013-06-14 48 / 51
49. ࠷ۙͷ͜ͱ . . ͓͠·͍ 2013-06-14 49 / 51
50. ϦϯΫ . . ࢀߟจݙ https://btrfs.wiki.kernel.org/ https://events.linuxfoundation.org/sites/events/files/ slides/LinuxCon_2013_NA_Eckermann_Filesystems_btrfs.pdf http://people.redhat.com/lczerner/files/btrfs_lczerner.pdf https://www.usenix.org/legacy/event/lsf07/tech/rodeh.pdf 2013-06-14 50 / 51
51. ϦϯΫ . . ը૾ http://www.flickr.com/photos/artofphotography-ramsner/9592744354 http://www.flickr.com/photos/surferbill/2506950772/ http://www.flickr.com/photos/rore/1304728223/ http://ja.wikipedia.org/wiki/ %E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB: Binary_search_tree.svg http://www.flickr.com/photos/protohiro/85504626/ http://www.flickr.com/photos/rubyji/74176893/ http://www.flickr.com/photos/rore/1304728223/ http://www.flickr.com/photos/dolfiedream/5060030894/ 2013-06-14 51 / 51