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sahib / rmlint

Extremely fast tool to remove duplicates and other lint from your filesystem
http://rmlint.rtfd.org
GNU General Public License v3.0
1.85k stars 128 forks source link

--dedupe doesnt dedupe all files for some reason. #629

Closed someone-somenet-org closed 10 months ago

someone-somenet-org commented 11 months ago

I came across a weird case of duplicates not getting deduplicated on btrfs (no snapshots on this FS, just raid10)

I use: rmlint --types="duplicates" --config=sh:handler=clone --no-crossdev --hidden /srv/[something]

While some files get deduplicated and rmlint --is-reflink "pathA" "pathB" returns 0 on those, some files seem to not be deduplicated and --is-reflink returns 1, even after manually running after a seemingly successful rmlint --dedupe "pathA" "pathB" on them.

In total it seems like 1/3 of all the duplicates in /srv/[something] seem to not be deduplicated.

strace'ing stuff doesnt really help either.

openat(AT_FDCWD, "pathA", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=25021930, ...}) = 0
uname({sysname="Linux", nodename="[something]", ...}) = 0
futex(0x7fbca0371fe8, FUTEX_WAKE_PRIVATE, 2147483647) = 0
openat(AT_FDCWD, "pathB", O_RDWR) = 4
fsync(3)                                = 0
fsync(4)                                = 0
ioctl(3, BTRFS_IOC_FILE_EXTENT_SAME or FIDEDUPERANGE, {src_offset=0, src_length=16777216, dest_count=1, info=[{dest_fd=4, dest_offset=0}]} => {info=[{bytes_deduped=16777216, status=0}]}) = 0
ioctl(3, BTRFS_IOC_FILE_EXTENT_SAME or FIDEDUPERANGE, {src_offset=16777216, src_length=8244714, dest_count=1, info=[{dest_fd=4, dest_offset=16777216}]} => {info=[{bytes_deduped=8244714, status=0}]}) = 0
close(3)                                = 0
close(4)                                = 0
exit_group(0)                           = ?

It seems that the dedup calls are sent and return 0, but nothing really happens.

filefrage pathA pathB returns 2 diffrent extent counts, rmlint --is-reflink "pathA" "pathB" returns 1.

cebtenzzre commented 10 months ago

What is the actual output of filefrag -vb1 pathA and filefrag -vb1 pathB? Note that small files cannot be deduplicated via reflinks because they have inline extents. (Although in this case, they appear to be sufficiently large.)

someone-somenet-org commented 10 months ago

pathA

Filesystem type is: 9123683e
File size of pathA is 25021930 (25022464 blocks of 1 bytes)
 ext:     logical_offset:        physical_offset: length:   expected: flags:
   0:        0.. 8122367: 3119203209216..3119211331583: 8122368:             shared
   1:  8126464.. 8163327: 3104252211200..3104252248063:  36864: 3119211335680: encoded,shared
   2:  8183808.. 8212479: 3104252227584..3104252256255:  28672: 3104252268544: encoded,shared
   3:  8548352.. 8679423: 3104252243968..3104252375039: 131072: 3104252592128: encoded,shared
   4:  8679424.. 9596927: 3119211331584..3119212249087: 917504: 3104252375040: shared
   5:  9596928.. 9727999: 3104252329984..3104252461055: 131072: 3119212249088: encoded,shared
   6:  9728000..10645503: 3119212249088..3119213166591: 917504: 3104252461056: shared
   7: 10645504..10776575: 3104252432384..3104252563455: 131072: 3119213166592: encoded,shared
   8: 10776576..10907647: 3104252538880..3104252669951: 131072: 3104252563456: encoded,shared
   9: 10907648..11038719: 3104252641280..3104252772351: 131072: 3104252669952: encoded,shared
  10: 11038720..11169791: 3104252743680..3104252874751: 131072: 3104252772352: encoded,shared
  11: 11169792..11300863: 3104252846080..3104252977151: 131072: 3104252874752: encoded,shared
  12: 11300864..11431935: 3104252952576..3104253083647: 131072: 3104252977152: encoded,shared
  13: 11431936..11563007: 3104253054976..3104253186047: 131072: 3104253083648: encoded,shared
  14: 11563008..11694079: 3104253161472..3104253292543: 131072: 3104253186048: encoded,shared
  15: 11694080..11825151: 3104253267968..3104253399039: 131072: 3104253292544: encoded,shared
  16: 11825152..12742655: 3119213166592..3119214084095: 917504: 3104253399040: shared
  17: 12742656..12873727: 3104253374464..3104253505535: 131072: 3119214084096: encoded,shared
  18: 12873728..13266943: 3119214084096..3119214477311: 393216: 3104253505536: shared
  19: 13266944..13398015: 3104253476864..3104253607935: 131072: 3119214477312: encoded,shared
  20: 13398016..13529087: 3104253583360..3104253714431: 131072: 3104253607936: encoded,shared
  21: 13529088..13660159: 3104253689856..3104253820927: 131072: 3104253714432: encoded,shared
  22: 13660160..13791231: 3104253796352..3104253927423: 131072: 3104253820928: encoded,shared
  23: 13791232..13922303: 3104253902848..3104254033919: 131072: 3104253927424: encoded,shared
  24: 13922304..14053375: 3104254013440..3104254144511: 131072: 3104254033920: encoded,shared
  25: 14053376..14315519: 3119214477312..3119214739455: 262144: 3104254144512: shared
  26: 14315520..14446591: 3104254119936..3104254251007: 131072: 3119214739456: encoded,shared
  27: 14446592..14577663: 3104254226432..3104254357503: 131072: 3104254251008: encoded,shared
  28: 14577664..14708735: 3104254332928..3104254463999: 131072: 3104254357504: encoded,shared
  29: 14708736..14839807: 3104254418944..3104254550015: 131072: 3104254464000: shared
  30: 14839808..14950399: 3104254550016..3104254660607: 110592:             encoded,shared
  31: 14958592..14962687: 3104254631936..3104254636031:   4096: 3104254668800: shared
  32: 14966784..14999551: 3104254636032..3104254668799:  32768:             encoded,shared
  33: 15007744..15011839: 3104254648320..3104254652415:   4096: 3104254676992: shared
  34: 15020032..15024127: 3104254652416..3104254656511:   4096:             shared
  35: 15036416..15060991: 3104254656512..3104254681087:  24576:             encoded,shared
  36: 15065088..15077375: 3104254660608..3104254672895:  12288: 3104254685184: encoded,shared
  37: 15085568..15089663: 3104254668800..3104254672895:   4096: 3104254681088: shared
  38: 15110144..15122431: 3104254672896..3104254685183:  12288:             encoded,shared
  39: 15151104..15155199: 3104254676992..3104254681087:   4096: 3104254713856: shared
  40: 15171584..15228927: 3104254681088..3104254738431:  57344:             encoded,shared
  41: 15233024..15347711: 3104254705664..3104254820351: 114688: 3104254742528: encoded,shared
  42: 15351808..15482879: 3104254750720..3104254881791: 131072: 3104254824448: encoded,shared
  43: 15482880..15613951: 3104254808064..3104254939135: 131072: 3104254881792: encoded,shared
  44: 15613952..15745023: 3104254865408..3104254996479: 131072: 3104254939136: encoded,shared
  45: 15745024..15876095: 3104254922752..3104255053823: 131072: 3104254996480: encoded,shared
  46: 15876096..16007167: 3104254980096..3104255111167: 131072: 3104255053824: encoded,shared
  47: 16007168..16138239: 3104255037440..3104255168511: 131072: 3104255111168: encoded,shared
  48: 16138240..16269311: 3104255102976..3104255234047: 131072: 3104255168512: encoded,shared
  49: 16269312..16400383: 3104255188992..3104255320063: 131072: 3104255234048: encoded,shared
  50: 16400384..16531455: 3104255270912..3104255401983: 131072: 3104255320064: encoded,shared
  51: 16531456..16662527: 3104255361024..3104255492095: 131072: 3104255401984: encoded,shared
  52: 16662528..16793599: 3104255451136..3104255582207: 131072: 3104255492096: encoded,shared
  53: 16793600..16924671: 3104255537152..3104255668223: 131072: 3104255582208: encoded,shared
  54: 16924672..17055743: 3104255614976..3104255746047: 131072: 3104255668224: encoded,shared
  55: 17055744..17092607: 3104255709184..3104255746047:  36864: 3104255746048: shared
  56: 17121280..17145855: 3104255746048..3104255770623:  24576:             shared
  57: 17154048..17285119: 3104255770624..3104255901695: 131072:             encoded,shared
  58: 17285120..17334271: 3104255868928..3104255918079:  49152: 3104255901696: encoded,shared
  59: 17338368..17362943: 3104255897600..3104255922175:  24576: 3104255922176: encoded,shared
  60: 17367040..17465343: 3104255909888..3104256008191:  98304: 3104255926272: encoded,shared
  61: 17469440..17600511: 3104255967232..3104256098303: 131072: 3104256012288: encoded,shared
  62: 17600512..17723391: 3104256053248..3104256176127: 122880: 3104256098304: encoded,shared
  63: 17727488..17858559: 3104256139264..3104256270335: 131072: 3104256180224: encoded,shared
  64: 17858560..17879039: 3104256225280..3104256245759:  20480: 3104256270336: shared
  65: 17948672..17977343: 3104256245760..3104256274431:  28672:             shared
  66: 17989632..18010111: 3104256274432..3104256294911:  20480:             shared
  67: 18022400..18153471: 3104256294912..3104256425983: 131072:             encoded,shared
  68: 18153472..18284543: 3104256380928..3104256511999: 131072: 3104256425984: encoded,shared
  69: 18284544..18415615: 3104256462848..3104256593919: 131072: 3104256512000: encoded,shared
  70: 18415616..18419711: 3104256548864..3104256552959:   4096: 3104256593920: shared
  71: 18423808..18468863: 3104256552960..3104256598015:  45056:             encoded,shared
  72: 18472960..19275775: 3119214739456..3119215542271: 802816: 3104256602112: shared
  73: 19288064..19308543: 3104256577536..3104256598015:  20480: 3119215554560: encoded,shared
  74: 19365888..19496959: 3104256581632..3104256712703: 131072: 3104256655360: encoded,shared
  75: 19496960..19542015: 3104256618496..3104256663551:  45056: 3104256712704: encoded,shared
  76: 19595264..19726335: 3104256634880..3104256765951: 131072: 3104256716800: encoded,shared
  77: 19726336..19836927: 3104256712704..3104256823295: 110592: 3104256765952: encoded,shared
  78: 19931136..19939327: 3104256786432..3104256794623:   8192: 3104256917504: encoded,shared
  79: 19943424..19988479: 3104256790528..3104256835583:  45056: 3104256798720: encoded,shared
  80: 19992576..20123647: 3104256794624..3104256925695: 131072: 3104256839680: encoded,shared
  81: 20123648..20254719: 3104256798720..3104256929791: 131072: 3104256925696: encoded,shared
  82: 20254720..20385791: 3104256806912..3104256937983: 131072: 3104256929792: encoded,shared
  83: 20385792..20516863: 3104256815104..3104256946175: 131072: 3104256937984: encoded,shared
  84: 20516864..20647935: 3104256823296..3104256954367: 131072: 3104256946176: encoded,shared
  85: 20647936..20721663: 3104256831488..3104256905215:  73728: 3104256954368: encoded,shared
  86: 22740992..22872063: 3104256835584..3104256966655: 131072: 3104258924544: encoded,shared
  87: 22872064..23003135: 3104256839680..3104256970751: 131072: 3104256966656: encoded,shared
  88: 23003136..23134207: 3104256843776..3104256974847: 131072: 3104256970752: encoded,shared
  89: 23134208..23265279: 3104256851968..3104256983039: 131072: 3104256974848: encoded,shared
  90: 23265280..23396351: 3104256860160..3104256991231: 131072: 3104256983040: encoded,shared
  91: 23396352..23437311: 3104256868352..3104256909311:  40960: 3104256991232: encoded,shared
  92: 23789568..23801855: 3104256872448..3104256884735:  12288: 3104257261568: encoded,shared
  93: 23805952..23842815: 3104256880640..3104256917503:  36864: 3104256888832: encoded,shared
  94: 23846912..23953407: 3104256901120..3104257007615: 106496: 3104256921600: encoded,shared
  95: 23957504..23982079: 3104256954368..3104256978943:  24576: 3104257011712: encoded,shared
  96: 24043520..24113151: 3104256966656..3104257036287:  69632: 3104257040384: encoded,shared
  97: 24121344..24182783: 3104256995328..3104257056767:  61440: 3104257044480: shared
  98: 24199168..24215551: 3104257056768..3104257073151:  16384:             encoded,shared
  99: 24305664..24330239: 3104257069056..3104257093631:  24576: 3104257163264: encoded,shared
 100: 24346624..24444927: 3104257085440..3104257183743:  98304: 3104257110016: encoded,shared
 101: 24969216..25022463: 3104257130496..3104257183743:  53248: 3104257708032: last,encoded,shared,eof
pathA: 89 extents found

pathB

Filesystem type is: 9123683e
File size of pathB is 25021930 (25022464 blocks of 1 bytes)
 ext:     logical_offset:        physical_offset: length:   expected: flags:
   0:        0.. 8122367: 3119203209216..3119211331583: 8122368:             shared
   1:  8126464.. 8163327: 3104252211200..3104252248063:  36864: 3119211335680: encoded,shared
   2:  8183808.. 8212479: 3104252227584..3104252256255:  28672: 3104252268544: encoded,shared
   3:  8548352.. 8679423: 3104252243968..3104252375039: 131072: 3104252592128: encoded,shared
   4:  8679424.. 9596927: 3119211331584..3119212249087: 917504: 3104252375040: shared
   5:  9596928.. 9727999: 3104252329984..3104252461055: 131072: 3119212249088: encoded,shared
   6:  9728000..10645503: 3119212249088..3119213166591: 917504: 3104252461056: shared
   7: 10645504..10776575: 3104252432384..3104252563455: 131072: 3119213166592: encoded,shared
   8: 10776576..10907647: 3104252538880..3104252669951: 131072: 3104252563456: encoded,shared
   9: 10907648..11038719: 3104252641280..3104252772351: 131072: 3104252669952: encoded,shared
  10: 11038720..11169791: 3104252743680..3104252874751: 131072: 3104252772352: encoded,shared
  11: 11169792..11300863: 3104252846080..3104252977151: 131072: 3104252874752: encoded,shared
  12: 11300864..11431935: 3104252952576..3104253083647: 131072: 3104252977152: encoded,shared
  13: 11431936..11563007: 3104253054976..3104253186047: 131072: 3104253083648: encoded,shared
  14: 11563008..11694079: 3104253161472..3104253292543: 131072: 3104253186048: encoded,shared
  15: 11694080..11825151: 3104253267968..3104253399039: 131072: 3104253292544: encoded,shared
  16: 11825152..12742655: 3119213166592..3119214084095: 917504: 3104253399040: shared
  17: 12742656..12873727: 3104253374464..3104253505535: 131072: 3119214084096: encoded,shared
  18: 12873728..13266943: 3119214084096..3119214477311: 393216: 3104253505536: shared
  19: 13266944..13398015: 3104253476864..3104253607935: 131072: 3119214477312: encoded,shared
  20: 13398016..13529087: 3104253583360..3104253714431: 131072: 3104253607936: encoded,shared
  21: 13529088..13660159: 3104253689856..3104253820927: 131072: 3104253714432: encoded,shared
  22: 13660160..13791231: 3104253796352..3104253927423: 131072: 3104253820928: encoded,shared
  23: 13791232..13922303: 3104253902848..3104254033919: 131072: 3104253927424: encoded,shared
  24: 13922304..14053375: 3104254013440..3104254144511: 131072: 3104254033920: encoded,shared
  25: 14053376..14315519: 3119214477312..3119214739455: 262144: 3104254144512: shared
  26: 14315520..14446591: 3104254119936..3104254251007: 131072: 3119214739456: encoded,shared
  27: 14446592..14577663: 3104254226432..3104254357503: 131072: 3104254251008: encoded,shared
  28: 14577664..14708735: 3104254332928..3104254463999: 131072: 3104254357504: encoded,shared
  29: 14708736..14839807: 3104254418944..3104254550015: 131072: 3104254464000: shared
  30: 14839808..14950399: 3104254550016..3104254660607: 110592:             encoded,shared
  31: 14958592..14962687: 3104254631936..3104254636031:   4096: 3104254668800: shared
  32: 14966784..14999551: 3104254636032..3104254668799:  32768:             encoded,shared
  33: 15007744..15011839: 3104254648320..3104254652415:   4096: 3104254676992: shared
  34: 15020032..15024127: 3104254652416..3104254656511:   4096:             shared
  35: 15036416..15060991: 3104254656512..3104254681087:  24576:             encoded,shared
  36: 15065088..15077375: 3104254660608..3104254672895:  12288: 3104254685184: encoded,shared
  37: 15085568..15089663: 3104254668800..3104254672895:   4096: 3104254681088: shared
  38: 15110144..15122431: 3104254672896..3104254685183:  12288:             encoded,shared
  39: 15151104..15155199: 3104254676992..3104254681087:   4096: 3104254713856: shared
  40: 15171584..15228927: 3104254681088..3104254738431:  57344:             encoded,shared
  41: 15233024..15347711: 3104254705664..3104254820351: 114688: 3104254742528: encoded,shared
  42: 15351808..15482879: 3104254750720..3104254881791: 131072: 3104254824448: encoded,shared
  43: 15482880..15613951: 3104254808064..3104254939135: 131072: 3104254881792: encoded,shared
  44: 15613952..15745023: 3104254865408..3104254996479: 131072: 3104254939136: encoded,shared
  45: 15745024..15876095: 3104254922752..3104255053823: 131072: 3104254996480: encoded,shared
  46: 15876096..16007167: 3104254980096..3104255111167: 131072: 3104255053824: encoded,shared
  47: 16007168..16138239: 3104255037440..3104255168511: 131072: 3104255111168: encoded,shared
  48: 16138240..16269311: 3104255102976..3104255234047: 131072: 3104255168512: encoded,shared
  49: 16269312..16400383: 3104255188992..3104255320063: 131072: 3104255234048: encoded,shared
  50: 16400384..16531455: 3104255270912..3104255401983: 131072: 3104255320064: encoded,shared
  51: 16531456..16662527: 3104255361024..3104255492095: 131072: 3104255401984: encoded,shared
  52: 16662528..16777215: 3104255451136..3104255565823: 114688: 3104255492096: encoded,shared
  53: 16777216..16793599: 3104255451136..3104255467519:  16384: 3104255565824: encoded,shared
  54: 16793600..16924671: 3104255537152..3104255668223: 131072: 3104255467520: encoded,shared
  55: 16924672..17055743: 3104255614976..3104255746047: 131072: 3104255668224: encoded,shared
  56: 17055744..17092607: 3104255709184..3104255746047:  36864: 3104255746048: shared
  57: 17121280..17145855: 3104255746048..3104255770623:  24576:             shared
  58: 17154048..17285119: 3104255770624..3104255901695: 131072:             encoded,shared
  59: 17285120..17334271: 3104255868928..3104255918079:  49152: 3104255901696: encoded,shared
  60: 17338368..17362943: 3104255897600..3104255922175:  24576: 3104255922176: encoded,shared
  61: 17367040..17465343: 3104255909888..3104256008191:  98304: 3104255926272: encoded,shared
  62: 17469440..17600511: 3104255967232..3104256098303: 131072: 3104256012288: encoded,shared
  63: 17600512..17723391: 3104256053248..3104256176127: 122880: 3104256098304: encoded,shared
  64: 17727488..17858559: 3104256139264..3104256270335: 131072: 3104256180224: encoded,shared
  65: 17858560..17879039: 3104256225280..3104256245759:  20480: 3104256270336: shared
  66: 17948672..17977343: 3104256245760..3104256274431:  28672:             shared
  67: 17989632..18010111: 3104256274432..3104256294911:  20480:             shared
  68: 18022400..18153471: 3104256294912..3104256425983: 131072:             encoded,shared
  69: 18153472..18284543: 3104256380928..3104256511999: 131072: 3104256425984: encoded,shared
  70: 18284544..18415615: 3104256462848..3104256593919: 131072: 3104256512000: encoded,shared
  71: 18415616..18419711: 3104256548864..3104256552959:   4096: 3104256593920: shared
  72: 18423808..18468863: 3104256552960..3104256598015:  45056:             encoded,shared
  73: 18472960..19275775: 3119214739456..3119215542271: 802816: 3104256602112: shared
  74: 19288064..19308543: 3104256577536..3104256598015:  20480: 3119215554560: encoded,shared
  75: 19365888..19496959: 3104256581632..3104256712703: 131072: 3104256655360: encoded,shared
  76: 19496960..19542015: 3104256618496..3104256663551:  45056: 3104256712704: encoded,shared
  77: 19595264..19726335: 3104256634880..3104256765951: 131072: 3104256716800: encoded,shared
  78: 19726336..19836927: 3104256712704..3104256823295: 110592: 3104256765952: encoded,shared
  79: 19931136..19939327: 3104256786432..3104256794623:   8192: 3104256917504: encoded,shared
  80: 19943424..19988479: 3104256790528..3104256835583:  45056: 3104256798720: encoded,shared
  81: 19992576..20123647: 3104256794624..3104256925695: 131072: 3104256839680: encoded,shared
  82: 20123648..20254719: 3104256798720..3104256929791: 131072: 3104256925696: encoded,shared
  83: 20254720..20385791: 3104256806912..3104256937983: 131072: 3104256929792: encoded,shared
  84: 20385792..20516863: 3104256815104..3104256946175: 131072: 3104256937984: encoded,shared
  85: 20516864..20647935: 3104256823296..3104256954367: 131072: 3104256946176: encoded,shared
  86: 20647936..20721663: 3104256831488..3104256905215:  73728: 3104256954368: encoded,shared
  87: 22740992..22872063: 3104256835584..3104256966655: 131072: 3104258924544: encoded,shared
  88: 22872064..23003135: 3104256839680..3104256970751: 131072: 3104256966656: encoded,shared
  89: 23003136..23134207: 3104256843776..3104256974847: 131072: 3104256970752: encoded,shared
  90: 23134208..23265279: 3104256851968..3104256983039: 131072: 3104256974848: encoded,shared
  91: 23265280..23396351: 3104256860160..3104256991231: 131072: 3104256983040: encoded,shared
  92: 23396352..23437311: 3104256868352..3104256909311:  40960: 3104256991232: encoded,shared
  93: 23789568..23801855: 3104256872448..3104256884735:  12288: 3104257261568: encoded,shared
  94: 23805952..23842815: 3104256880640..3104256917503:  36864: 3104256888832: encoded,shared
  95: 23846912..23953407: 3104256901120..3104257007615: 106496: 3104256921600: encoded,shared
  96: 23957504..23982079: 3104256954368..3104256978943:  24576: 3104257011712: encoded,shared
  97: 24043520..24113151: 3104256966656..3104257036287:  69632: 3104257040384: encoded,shared
  98: 24121344..24182783: 3104256995328..3104257056767:  61440: 3104257044480: shared
  99: 24199168..24215551: 3104257056768..3104257073151:  16384:             encoded,shared
 100: 24305664..24330239: 3104257069056..3104257093631:  24576: 3104257163264: encoded,shared
 101: 24346624..24444927: 3104257085440..3104257183743:  98304: 3104257110016: encoded,shared
 102: 24969216..25022463: 3104257130496..3104257183743:  53248: 3104257708032: last,encoded,shared,eof
pathB: 90 extents found
cebtenzzre commented 10 months ago

If you compare extent 52 of file A to extents 52 and 53 of file B, it looks like the files are indeed reflinked, just in an unusual way: file A uses a single extent to represent the data, whereas file B uses two extents references with the same physical start offset.

This is tricky, because --is-reflink doesn't actually look at the file data to determine if files are reflinked, so it doesn't know that the first 16K and last 16K of that extent have the same content. Even I am just assuming that is true, since FIDEDUPERANGE has been run on them.

I wonder how the extents ended up like that in the first place. Perhaps you have run something like bees on this filesystem? As far as I know, plain rmlint --dedupe/FIDEDUPERANGE or cp --reflink cannot create this situation.

If this bothers you, you could defrag the files in question—breaking all reflinks—and try to dedupe them again with rmlint. compsize may tell you that your file data is actually well-deduplicated already - compare the "Referenced" and "Uncompressed" columns.

someone-somenet-org commented 10 months ago

Thanks. Since i have seen the outputs of filefrag I started experimenting with btrfs and compression and defrag. It seems no compression, compress=lzo and compress-force=lzo yields hugely diffrent amounts of extents.

It seems i cannot make btrfs make only 1 extent of the file, Im not getting below 40 extents, with force lzo compression i get to like 200 extents...

The files were both uploaded via rsync - their name is quite diffrent, so I didnt even expect them to be identical - at least it would seem unlikely, because of their name and the folder's.

cebtenzzre commented 10 months ago

btrfs does have a maximum extent size. It is smaller for compressed extents than uncompressed extents. The main purpose of defrag is to at least reduce the number of extents, with a side-effect of breaking reflinks, and the option of changing the compression algorithm since the data is being re-written anyway. I don't think there's any reason you should force compression, the default heuristic is there for a reason.