  The Software-RAID HOWTO
  Jakob OEstergaard (jakob@ostenfeld.dk)
  v. 0.90.6 31st of October 1999
  } @ (kasai@heart-pot.co.jp)
  v.1.0 04 December 1999

   HOWTO ł́ALinux  Software RAID g@ɂċLq܂B
  ܂ ftp://ftp.fi.kernel.org/pub/linux/daemons/raid/alpha 
  \ RAIDpb`肷Kv܂BHOWTO ̌ http://osten-
  feld.dk/~jakob/Software-RAID.HOWTO/ ɂ܂B
  ______________________________________________________________________

  ڎ

  1. Cg_NV
     1.1 Disclaimer^
     1.2 Kv

  2. Ȃ RAID Ȃ̂H
     2.1 I
     2.2 p
     2.3 RAID x
        2.3.1 \fBXN
     2.4 RAIDł̃XbsO

  3. n[hEFA̖
     3.1 IDE \
     3.2 zbgXbv
        3.2.1 IDE hCũzbgXbv
        3.2.2 SCSI hCũzbgXbv
        3.2.3 SCA ɂzbgXbv

  4. RAID ZbgAbv
     4.1 ʓIȃZbgAbv
     4.2 jA[h
     4.3 RAID-0
     4.4 RAID-1
     4.5 RAID-4
     4.6 RAID-5
     4.7 The Persistent Superblock
     4.8 Chunk TCY
        4.8.1 RAID-0
        4.8.2 RAID-1
        4.8.3 RAID-4
        4.8.4 RAID-5
     4.9 mke2fŝ߂̃IvV
     4.10 o
     4.11 RAID Ńu[g
     4.12 RAID ̃[gt@CVXe
        4.12.1 @ 1
        4.12.2 @ 2
     4.13 RAID Ńu[gVXe
        4.13.1 W[gp RAID Ńu[g
     4.14 

  5. eXg
     5.1 hCǔ̏V~[V
     5.2 f[^̔jV~[V

  6. č\z
     6.1 fBXŇ̏Ⴉ̉

  7. ptH[}X
     7.1 RAID-0
     7.2 TCQ ɂ RAID-0
     7.3 RAID-5
     7.4 RAID-10

  8. NWbg

  ______________________________________________________________________

  1.  Cg_NV

   howto  Jakob OEstergaard ɂ̂łB҂ Ingo Molnar
  (mingo@chiara.csoma.elte.hu) -- RAID J҂̂ 1 l --A Linux-
  RAID [OXg(linux-raid@vger.rutgers.edu) Ƒ̐lXƂ̊Ԃ
  킳ꂽ̓dq[ɊÂ̂łB
  Software-RAID HOWTO łɑ݂ɂ炸A HOWTO 
  ꂽ̂ɂ͂킯܂B͌Â HOWTO ł́Aʂ̃J[lɊ
  鋌 Software RAID ɂĂĂȂłB
  HOWTO ́AŋߊJꂽVX^C RAID ̎gɂċLq
  Ă܂BVX^C RAID ɂ͋ RAID ɂ͂ȂA̋@
  \܂B

  W 2.2.X J[ĺA HOWTO ŋLqV RAID 𒼐ڃT|
  [gĂ܂񂩂Apb`KvɂȂ܂BW 2.2.X J[l
   RAID T|[g̓oOAVX^C RAID \tgEFAɂ
  dvȂ̋@\Ă܂B

  ̎M_ł 2.4 ̃J[lo鎞ɂ́i]Iϑɂ N
  1999 ÑNX}XjAVX^C RAID gݍ܂ꂻłB
  ܂ł́AŃJ[lɎŃpb`𓖂ĂKv܂B

  Alan Cox ̎ɂ -ac J[lg܂ˁB
  A͐VRAID܂܂Ă܂BȂAJ[lɃpb`
  ĂԂ͂Ԃ܂B

  Ȃ RAID ɂĒmĂȂA HOWTO ̏ɂ͂܂
  Ȃ̂邩܂񂪁A͓ǂݔ΂Ă܂Ă
  B

  1.1.  Disclaimer^

  ۏ؁|

  RAID ͎ɂ͈肵Ă悤Ɍ܂Ȃ̐lXɂƂĂ
  肵Ă悤łA܂삵Ȃ܂BȂSẴf
  [^AdAgbNɂ͂˂悤ȎɂȂƂĂA
  ͎J҂̐ӔCł͂܂BRAID \tgEFA₱̏́A
  Ȃg̐ӔCiat your own riskjŗpĂB\tgEFA
  ̏ɂ؂̕ۏ؂͂܂B̑OɁASĂ̂Ȃ̃f[^
  obNAbv悤ɁI]΂ʐ̏łB

  fĂ܂Ag Software RAID ̈萫Ɋւɂ
  Ƃ͈x܂B̃}Vł͎gĂ܂񂪁A
  ̖NĂ܂񂵁AsvcȃNbVAs肾Ƃ
  lƂ܂B

  1.2.  Kv

   HOWTO ł́Aŋ߂ 2.2.x  2.0.x J[lɑΉ raid0145
  pb`𓖂Ă̂ƁAraidtools ̃o[W 0.90 gĂƉ肵
  ܂Bǂ ftp://ftp.fi.kernel.org/pub/linux/daemons/raid/alpha 
  ܂BRAID pb`Araidtools pbP[WAJ[ĺA
  ƑΉĂo[WgĂBRAID pb`ŐṼJ[l
  ɗpłȂȂ΁AÂJ[lg悤ɁB

  i󒍁F{
  ftp://ftp.jp.kernel.org/pub/linux/daemons/raid/alpha/ pł܂B
  |󎞓_ł̍ŐVł́Aȉ̒ʂłj

  RAID pb`
    raid0145-19990824-2.0.37.gz
    raid0145-19990824-2.2.11.gz

  raidtools
    raidtools-19990824-0.90.tar.gz

  2.  Ȃ RAID Ȃ̂H

  RAID gƗǂƂ񂠂܂BႦ΁ÃfBXN
  傫uzIȁvfoCXɌ\́AptH[}XAď
  łB

  2.1.  I

  Linux RAID ́AقƂǂ̃ubN^foCXœ삵܂Bgpn
  [hfBXN IDEASCSIA͗҂݂Ă悤ƁA͏dv
  ł͂܂Blbg[Nz (Network Block Device - NBD) ł
  Ƃ񍐂܂B

  hCuɑ΂oX̑x͏[ɑKv܂BehCu 10
  MB/s ̔\͂AoX 40 MB/s Ȃ悤ȏꍇ
  ́AUW(UltraWide) oX 1 { 14  UW-SCSI hCuڑ悤
  Ƃ͂Ȃ悢ł傤B܂ IDE oXȂA1 {̃oXɃfoCX
   1 䂾ɂׂłBIDE fBXN}X^[^X[u\ɂ
  ̂̓ptH[}XȂ܂BIDE ł1 ȏ̃hCuoX
  ɑ΂ANZX͗ǂ܂Bŋ߂̃}U[{[h́Aʂ 2 {
  IDE oXĂ܂A悯ȃRg[𔃂ƂȂ 2 
  ̃fBXN RAID \邱Ƃł܂B

  RAID ĆAt@CVXẽCƂ͂܂֌W܂B
  ̃ubNfoCXƓlɁARAID foCX̏ɂ͂ǂȃt@CVX
  eł\zł܂B

  2.2.  p

  uRAIDvƂ́uLinux Software RAIDvӖ̂Ƃ܂B
  HOWTO ł Hardware RAID ɂĂ͈܂B

  u\ɂċLqꍇɂ́AfBXN̐ƃTCY̕\L߂Ă
  ƕ֗łB N ́AfBXNACi\fBXN܂܂Ȃj̒
  ŁAANeBuȃfBXN̐̂Ƃ܂B S ͓ɒfȂ
  AfBXNAC̒ōłhCũTCYƂ܂B P
  ̓fBXNAC̒1̃fBXÑptH[}X\APʂ MB/s
  Ƃ܂BP gꍇɂ́AׂẴfBXN̐\Ɖ肵
  Ă܂A͏ɐƂ͌Ȃ܂B

  ufoCXvƁufBXNvقړӖŎgĂ_ɒӂĂ
  BʏARAID foCX\z邽߂ɎgfoCX̓fBXN
  p[eBVłAKfBXNŜłKv͂܂Bł
   1 ̃fBXN̏ł̃p[eBV RAID ɂ
  ӖȂȂ̂ŁAfoCXƃfBXN͒PɁuقȂfBXÑp[
  eBVvӖ̂Ƃ܂B

  2.3.  RAID x

  Linux RAID pb`ŃT|[g邱ƂȒPɏĂ܂BɊ
  bI RAID ̏łALinux ɂ RAID x̎œʂȂ
  ɂẮALqĂ܂BRAID 悭mĂl͂̃ZN
  VXLbvĂBȂɂ肪߂Ă΂̂
   :)

  ݂ Linux p RAID pb`T|[ĝ͈ȉ̊exł|

  o  jA[h

     o  ̃fBXNA1 ̕IȃfoCXɌ郂[hłB
        fBXN݂͂Ɂuǉv̂ŁARAID foCXɏ
        ƁAŏɃfBXN 0 ɁAtɂȂ玟ɃfBXN 1 ɁA܂
        tɂȂfBXN 2 ɁAƏ܂邱ƂɂȂ܂BefB
        XN͓TCYłKv͂܂BTCY͂ł͏dvł
        Ȃ̂ł :)

     o  ̃xɂ͏璷͂܂B1 ̃fBXNNbV
        ƁA炭SẴf[^\܂Błt@CV
        Xef[^̑傫Ȃ܂肪킯łA^ǂ
        c኱̃f[^񕜂ł邱Ƃ\ƂĂ͂
        B

     o  ǂݏ̃ptH[}X͒PƂ read/write ł͌サ܂񂪁A
        ̃[U[foCXgꍇAȂ 1 ̃fBXNɃA
        NZXĂuԂɁA̒N 2 ̃fBXNɃANZXĂ
        ƂƂN蓾܂B̂悤ȏꍇAptH[}X͌
        ܂B

  o  RAID-0

     o  uXgCvv[hƂĂ΂܂BjA[hƎĂ܂A
        ǂݏ̃foCXɕɍsƂ낪Ⴂ܂BeX
        foCX͂قړTCYłKv܂BSẴANZX
        ɎŝŁÃfoCX͑Sē悤Ɏg܂B1
        ̃foCXєđ傫ꍇA̓ʂ̃Xy[X
        RAID foCXƂĎg܂AfoCX̏I̕ɃANZX
        Ƃɂ́Â傫fBXNɃANZX邱Ƃɂ
        ARptH[}X͈܂B

     o  jA[hƓlÃxɂ璷͂܂BjA[
        hƈႤ̂́A1 ̃hCȕႵꍇłĂA؂̃f
        [^~ƂłȂƂƂłBRAID-0 hCu
        OƂ RAID foCX̂镔̘AIȃubN
        Ƃ킯ł͂ȂAfoCX̎鏊炯ɂȂ
        ł傤B e2fsck ͂̂悤ȃfoCXقƂ
        ǉ񕜂邱Ƃ͂łȂł傤B

     o  ǂݏ̃ptH[}X͌サ܂Aǂݏ̓foCXŕ
        Ɏs邩łBꂪAʏ RAID-0 𑖂点邱Ƃ̎ȗ
        RłBoX[ɑ΁AptH[}X N * P MB/s ɋ߂
        Ȃ܂B

  o  RAID-1

     o  ͎ۂɏ璷ŏ̃[hłBRAID-1  2 ȏ
        fBXNΗpł܂B\̃fBXNpӂĂƂ
        ł܂B̃[h́A1 ̃fBXN𑼂̃fBXNŐmɃ~
        [킯łBefBXN͓TCYłȂ΂Ȃ܂
        B1 ̃fBXN傫ƂĂARAID foCX͍ł
        fBXNƓTCYɂȂĂ܂܂B

     o  N-1 ܂ł̃fBXNOĂ(܂͌̏ႵĂ)Af[^
        ܂ׂĊSłBpł\fBXNAVXeiSCSI
        hCo[ IDE `bvZbgȂǁjcĂꍇAhC
        ȕ̔AɃ~[̍č\z\fBXN̂ 1 
        Ŏn܂܂B

     o  ǂݍ݂̃ptH[}X N * P ɋ߂lɂȂ܂A
        ̓foCX 1 ̏ꍇƓȉɂȂ܂Bǂݍ݂͕񓮍
        ł܂A݂ł CPU  N f[^𑗂Ȃ΂ȂȂ
        łiN ̃f[^̓̃Rs[efBXNɑȂ
        ȂȂ̂łjB

  o  RAID-4

     o   RAID x́A܂g܂B3 ȏ̃fBXN
        ΎgƂł܂BSɃ~[ɁA1 ̃h
        CuɃpeBۂāÃfBXNɂ RAID-0 ̂悤ȕ@
        Ńf[^킯łB1 ̃fBXNpeB̂߂ɗ\
        邽߁AAC̃TCY (N - 1) * S ƂȂ܂BS ͍ł
        ̂̃TCYłBRAID-1 ̏ꍇ̂悤ɁAfBXÑTCY
        łׂłBȂƏ (N - 1) * S ̌ɏ]AA
        CōłhCũTCYł S ɂđ
        邱ƂɂȂ܂B

     o  1 ̃hCȕႵȂpeB񂪎gASẴf[
        ^Čł܂B2 ̃hCȕႷƁASẴf[^
        ܂B

     o  ̃x܂gȂ̂́ApeB 1 ̃hCu
        ɏWĂ܂łB̃fBXN̂ 1 ɏ݂
        N邽тɁȀ͍XVȂ΂ȂȂ̂łB܂p
        eBfBXN[ȂƁA{glbNɂȂĂ܂
        ܂B܂ܑ̒xfBXNƔɑfBXNĂ
        悤ȂA RAID x͖ɗ܂B

  o  RAID-5

     o  葽̕fBXNĂɏ璷ƂA
        ͂炭łɗ RAID [hłBRAID-5  3 ȏ
        fBXNŎgƂł܂B\̃fBXNpӂĂƂ
        ł܂BʂƂ RAID-5 foCXTCY RAID-4 Ɠl (N
        - 1) * S ƂȂ܂BRAID-5  RAID-4 ̊Ԃ̑傫ȈႢ́Ap
        eB񂪊ehCuɋψɕUƂƂłBł
        RAID-4 ̃{glbN邱Ƃł܂B

     o  1 ̃fBXN̏ႵĂpeB̂ŁASẴf[^
        SłB\fBXNpłȂAfoCX̏̒ɍč\
        zn܂܂B2 ̃fBXNɌ̏ႵĂ܂ƑSẴf[
        ^܂BRAID-5  1 ̃fBXN̏؂邱Ƃł
        ܂ 2 ȏ͖łB

     o  ʏAǂݏƂɃptH[}X͌サ܂Aǂ̒x
        \邱Ƃ͍łB

  2.3.1.  \fBXN

  \fBXŃAANeBuȃfBXN̂ 1 䂪̏Ⴗ܂ RAID
  ɎQȂfBXNłBfoCX̏ႪƂ̃foCX́us
  ǁvƃ}[NApłŏ̗\fBXN̏Œɍč\zn
  ܂B

  ܂ RAID-5 ɗ\fBXN𑕔ƁASiiɌシ邱Ƃ
  Ȃ܂B1 ̃fBXN̏ႵƂĂ\fBXNɂď璷
  ێĂ΁Â܂ܓ삵邱ƂɂȂĂ΂炭̊ԂȂ狖
  ełł傤B

  VXefBXNNbVmɏ؂Ƃۏ؂͂܂
  BRAID C̓foCX̏܂Ȃ΂Ȃ܂񂪁ASCSI
  hCoG[ɔł܂AIDE `bvZbgł܂Ă
  ܂Aɂ悤ȂƂ낢N\܂B

  2.4.  RAIDł̃XbsO

  swap  ptH[}X̂߂ RAID gKv͂܂Bfstab
  t@Cɂĕ̃Xbvp[eBVɓDx^ƁAJ
  [lgXbvXgCvɂ邱Ƃł邩łB

  ̂߂ fstab ̋Lq́|

  /dev/sda2       swap           swap    defaults,pri=1   0 0
  /dev/sdb2       swap           swap    defaults,pri=1   0 0
  /dev/sdc2       swap           swap    defaults,pri=1   0 0
  /dev/sdd2       swap           swap    defaults,pri=1   0 0
  /dev/sde2       swap           swap    defaults,pri=1   0 0
  /dev/sdf2       swap           swap    defaults,pri=1   0 0
  /dev/sdg2       swap           swap    defaults,pri=1   0 0

  ̓Xbv 7  SCSI foCXŕɂݒłBRAID ̕Kv
  ͂܂B͂ԃJ[l̋@\ƂĂ̂łB

  Xbv RAID g̗ŔApłBu[ĝ߂
  Ⴆ RAID-1 foCXɃVXeZbgAbv΁AVXe̓fBX
  NENbV؂邱Ƃł܂BXbvsǃfoCX
  ƂA܂ԈႢȂ܂ƂɂȂ܂BRAID-1 foCXXb
  vɂ΂̖Ă܂B

  ŐV RAID pb`ł RAID ł̃XbsO͈SȂ͂łBȑO
  fbhbN̉\߁ARAID ł̃Xbv͈SƂ͌
  łA݂ł͏Cꂽ͂łB

  RAID foCX̃t@CVXeŁAXbvEt@C̒ RAID 
  \邱Ƃł܂B邢 RAID foCXXbvp[eBV
  Ƃč\邱Ƃł܂BɂāARAID foCX͒PȂub
  NfoCXȂ̂łB

  3.  n[hEFA̖

  ̃ZNVł́A\tgEFA RAID 𑖂点ꍇ̃n[hEFAɊ
  ďqׂĂ܂B

  3.1.  IDE \

  IDE fBXN RAID 𑖂点邱Ƃ́AɌIȂƂłBDꂽ
  \܂BہAV RAID VXe\ꍇɁAIDE h
  CuƃRg[̍̉iɂ͈l̉l܂B

  o  I萫| IDE hCúA`I SCSI hCuiႢ
     悤łBł IDE hCu̕ۏ؊Ԃ͊TˈNł
     ɁASCSI hCuɂĂ 3 ` 5 NłBƂ̂
     tFAł͂ȂłAIDE hCu͍肪eŁAuh
      IDE hCu SCSI hCȕႵ₷悤łB
     uhł́ASCSI  IDE Sɓ̃JjYgĂ܂B
     vɁ|xꑁfBXNׂ͂ĉ܂AɂĂ͊o
     ĂȂ΂Ȃ܂B

  o  f[^S| ȑÓAIDE ł̓oXɑf[^ۂɃfBXN
     ɏꂽf[^ƁÂł邾낤Ƃۏ؂@
     łBpeB`FbNTȂǂĂ̂łBUltra-
     DMA ł́AIDE hCu󂯂f[^ɂ̓`FbNTt̂ŁAf
     [^邱Ƃ͂܂Ȃł傤B

  o  \| IDE ̐\ɂĂœOIɏ͂܂BȒP
     ɏƁ|

     o  IDE hCu͑i12 MB/s ȏj

     o  IDE  SCSI  CPU I[o[wbhiꂪȎC
        Hj
     o  IDE oX 1 { 1 IDE hCuƂ邱ƁBX[ufBX
        N͐\䖳ɂ܂B

  o  Qɐ| ʏ IDE hCóȀႵ IDE foCX
     Ăł܂Ƃ͂܂BRAID C̓fBXN̏
     }[NāARAID x 1 ȏ𗘗pĂ̂ł΁Aei
     X̂߂ɒ~܂Ń}V͂Ɠ͂łB

  IDE oX 1 {ɂ IDE fBXN 1 䂾ɂ邱Ƃ́Aɏdv
  B2 ̃fBXNȂƐ\䖳ɂ邾łȂA1 ̃fBX
  N̏ႷƁAoX̂̏Ⴕ悤ɂȂA 2 Ƃ̏Ⴕ
  ƓɂȂ܂B̏ɋ RAID \iRAID x1,4,5jł́A1 
  ̃fBXŇ̏͋~܂A2 ̃fBXN̏i1 ̃fBXŇ
  ̂߂ɃoX 2 ̃fBXNgȂjƁARAID ACŜ
  gȂȂ܂B܂AoX̃}X^[EhCȕႷƁAX[
  u܂ IDE Rg[邩܂B1 {̃oXɂ 1 
  ̃hCuBꂪ[łB

  PCI IDE Rg[ɂ͈c܂B80 ho 2 { 4
  { IDE oXɓ܂BSCSI fBXNɑ΂ IDE fBXN͔
  ł̂ŁAT^IȃVXeɕt邱Ƃł(Ă) 8 x
  ̃fBXNŗǂȂAIDE fBXNAC͖{ɑf炵ƌ
  ł傤i IDE Rg[̂߂ PCI Xbg̋󂪕Kv
  jB

  3.2.  zbgXbv

  ͂΂炭̊ Linux J[lEXg̃zbgȘbłBhC
  ũzbgXbv͂x܂ŃT|[gĂ܂A܂ȒPȂ
  ł͂܂B

  3.2.1.  IDE hCũzbgXbv

  IDE ͊{IɃzbgXbvł܂BIDE hCoW[i2.2
  V[ỸJ[lŉ\jƂăRpCĂāAhCǔ
  ɍă[h΂܂܂B IDE Rg[g
  ɂȂ邩܂̂ŁAfɓd؂ăhCuւ
  _E^C͒Zčςނł傤B

  n[hEFAj󂷂邩ȂƂdCIȖƁAȖ
  ̓fBXNꂽƂ IDE oXăXLȂ΂ȂȂ
  ƂłB݂ IDE hCoł͂ł܂BVfBXNÂ
  ̂ 100% (WIgȂ)ȂoXăXLɓ
  ܂񂪁A܂߂ł傤B

  3.2.2.  SCSI hCũzbgXbv

  ʂ SCSI n[hEFAzbgXbvɂ͑ΉĂ܂B
  삷邩܂BSCSI hCooX̍ăXLAfoCX
  OAǉT|[gĂ΁AzbgXbvł邩܂
  Bʂ SCSI oXł̓VXeɉ΂ĂԁAfoCX
  Ă͂Ȃ͂łA܂삷\܂i
  n[hEFA񂪂ĂオďIĂ܂܂jB

  fBXNł SCSI C ͐c͂łA܂SĂ SCSI
  hCȍ󋵂ɑΉĂ킯ł͂܂B1 ̃fBXN
  Ȃ SCSI hCoʂƂɂȂƁAVXeŜA
  ɂȂ܂AȂ񂶂zbgvOɋ͂܂B

  3.2.3.  SCA ɂzbgXbv

  SCA g΃zbgvOfoCXɂȂł傤BAɂ͂
  p邽߂̃n[hEFAȂłAɎgĂƂb
  ̂ŁAɂďqׂ邱Ƃ͂ł܂B

  ŗVт̂ł΁ASCSI  RAID ̓\ɂĂ̒mKv
  łBۂɂĂ݂邱ƂłȂ̂łŏ킯ɂ͂܂
  Ȃ 2A3 ̎肪^邱Ƃł܂|

  o  linux/drivers/scsi/scsi.c  remove-single-device  grep

  o  raidhotremove  raidhotadd ɒڂĂ

  SĂ SCSI hCofoCX̒ǉƍ폜T|[gƂ킯ł
  ܂BJ[l 2.2 V[Ył́AȂƂ Adaptec 2940 
  Symbios NCR53c8xx hCoT|[g悤łBɂĕ
  ĂlΊӂ܂DDD

  4.  RAID ZbgAbv

  4.1.  ʓIȃZbgAbv

  ̂̂́Aǂ RAID xłKvƂ̂ł|

  o  J[lBł 2.2.X ܂͍ŐV 2.0.X. ł傤B

  o  RAID pb`Bŋ߂̃J[lɗpłpb`Ȁꍇ
     B

  o  RAID tools

  o  EρAsUACɓ̃JtFC

  SẴ\tgEFA ftp://ftp.fi.kernel.org/pub/linux Ō
  ܂BRAID tools ƃpb` daemons/raid/alpha TufBNg
  ܂BJ[l kernel TufBNgŌ܂B

  J[lɃpb`𓖂āAgx RAID T|[g܂߂悤ɍ\
  ܂BăRpCACXg[sȂ܂B

  ɁARAID tools WJĐݒ肵ARpCACXg[sȂ
  Bi󒍁Fconfigure, make, make install Ŏ̏ꍇ OK łj

  ̎_Ńu[g /proc/mdstat Ƃt@CmFł͂
  B̃t@C͂Ȃ́uFBvƂƂĂĂ
  Bcat /proc/mdstat sēemFĂ݂ƁAo^Ă
  RAID ̓킩܂iႦ RAID [hjB܂ RAID foCX͑
  ݂Ȃ͂łB

  RAID Ɋ܂߂p[eBV܂B

  ̓[hɓeɂȂ܂B

  4.2.  jA[h

  ł́A܂ȂƂ 2 ̃p[eBVpӂ܂Bꂼ͓
  傫łKv͂܂iAłΓɁjB݂
  킯łB

  /etc/raidtab t@Cݒ肵܂B raidtab ɃjA[h 2 
  ̃fBXNœ삳邽߂̐ݒsȂ܂Be͈ȉ̒ʂł|

  raiddev /dev/md0
          raid-level      linear
          nr-raid-disks   2
          persistent-superblock 1
          device          /dev/sdb6
          raid-disk       0
          device          /dev/sdc5
          raid-disk       1

  \fBXN͂ł̓T|[g܂BfBXN񂾂AAC
  AɂȂ܂B\fBXNɒu͂܂B

  ł́AAC܂傤BR}hł݂܂B

    mkraid /dev/md0

  ŃAC persistent superblock AACn
  ܂B

  /proc/mdstat ĂBACĂlq܂B

  Ńt@CVXe쐬邱Ƃł܂B}Eg fstab ɋL
  qȂǁÃfoCXƓl̎ł܂B

  4.3.  RAID-0

  قړTCY 2 ȏ̃foCXpӂ܂B̗eʂ̌
  AɃANZX邱ƂɂĐ\}킯łB

  /etc/raidtab t@Cݒ肵܂Bȉ͂̈ł|

  raiddev /dev/md0
          raid-level      0
          nr-raid-disks   2
          persistent-superblock 1
          chunk-size     4
          device          /dev/sdb6
          raid-disk       0
          device          /dev/sdc5
          raid-disk       1

  jA[hƓlɁA\fBXN̓T|[g܂BRAID-0 ɂ͏
  Ȃ̂ŁAfBXNʂƃACAɂȂ܂B

  AC邽߂Ɉȉ̃R}hł݂܂B

    mkraid /dev/md0

  X[p[ubNARAID foCXn킯łBN
  Ă̂ /proc/mdstat ĂBfoCXĂ邱
  ͂łB

   /dev/md0 tH[}bg}EgAႮᗐp鎖ł
  悤ɂȂ܂B

  4.4.  RAID-1

  قړTCY 2 ̃foCXpӂ܂A݂Ƀ~[킯
  łBł΂ 1 foCXpӂ܂傤Bҋ@p̗\
  fBXNƂ܂B\fBXN̓ANeBuȃfoCXꂽɁA
  IɃ~[Ă܂B

  /etc/raidtab t@Cݒ肵܂|

  raiddev /dev/md0
          raid-level      1
          nr-raid-disks   2
          nr-spare-disks  0
          chunk-size     4
          persistent-superblock 1
          device          /dev/sdb6
          raid-disk       0
          device          /dev/sdc5
          raid-disk       1

  \fBXNꍇÂ悤ȎwsȂfoCXǉ邱Ƃ
  ł܂B

          device          /dev/sdd5
          spare-disk      0

  ̏ꍇ nr-spare-disks Gg 1 ɐݒ肷̂YȂ悤ɁB

  āARAID pӂ܂B~[ 2 ̃foCX̓e
  ܂Ŋ܂߂ē悤ɍ\zȂ΂Ȃ܂ifoCX͂܂tH[
  }bgĂȂ̂ŁA債ł͂ȂłjB

  ~[̏JnR}hł݂܂B

    mkraid /dev/md0

  /proc/mdstat t@C`FbN܂傤B/dev/md0 foCX̃~[
  č\zn܂ĂA\zƂ̏I\莞m邱Ƃł
  ܂B

  č\z̓ACh I/O ohgĂȂ܂AVXe͈
  OƂ܂ς炸@qɓ삵͂łBfBXN LED Ȃ
  Ă͂łB

  č\zvZX͓ߓIȂ̂ŁA~[č\zƂĂfoCXg
  Ƃł܂B

  č\z̐isɃfoCXtH[}bgĂ݂ĂBƓ삷
  ͂łB܂Ač\z̐isłĂ}EgĎgƂł
  Bč\zɃfBXNꂽ肵AႠ^Ƃ
  悤܂񂪁B

  4.5.  RAID-4

  ӁI g͂̐ݒł̓eXgĂ܂Bȉ̐ݒ͂܂ŗ\z
  łAۂɑ点Ƃ͂܂B

  3 ȏ̂قړTCỸfoCXpӂ܂B1 єđ
  ̂łˁB 1 ̑傫ȃfoCXƂA璷
  킯łB

  /etc/raidtab t@Cݒ肵܂|

  raiddev /dev/md0
          raid-level      4
          nr-raid-disks   4
          nr-spare-disks  0
          persistent-superblock 1
          chunk-size      32
          device          /dev/sdb1
          raid-disk       0
          device          /dev/sdc1
          raid-disk       1
          device          /dev/sdd1
          raid-disk       2
          device          /dev/sde1
          raid-disk       3

  \fBXNΓlɓĂBȉ̂悤Ɂ|

          device         /dev/sdf1
          spare-disk     0

  ŃAC̏ł܂BʂÃR}hłł
  B

     mkraid /dev/md0

  foCXtH[}bgO ``mke2fs ̂߂̃IvV'' ZNV
  ĂB

  4.6.  RAID-5

  3 ȏ̂قړTCỸfoCXpӂ܂BA璷
  ԂŎg킯łB\fBXNł傤B
  ̃fBXN͑̃foCX̏Ⴗ܂ł͎g܂B

  N ̃foCXgƂāAł̂̃TCY S ƂƁAA
  C̃TCY iN - 1) * S ƂȂ܂B́uꂽvXy[XAp
  eBi璷ĵ߂Ɏg킯łBǂ̃fBXN̏ႵĂS
  Ẵf[^͊SȂ܂܂łB 2 ̃fBXN̏ႵĂ܂
  ASẴf[^邱ƂɂȂ܂B

  /etc/raidtab t@Cݒ肵܂|

  raiddev /dev/md0
          raid-level      5
          nr-raid-disks   7
          nr-spare-disks  0
          persistent-superblock 1
          parity-algorithm        left-symmetric
          chunk-size      32
          device          /dev/sda3
          raid-disk       0
          device          /dev/sdb1
          raid-disk       1
          device          /dev/sdc1
          raid-disk       2
          device          /dev/sdd1
          raid-disk       3
          device          /dev/sde1
          raid-disk       4
          device          /dev/sdf1
          raid-disk       5
          device          /dev/sdg1
          raid-disk       6

  \fBXNꍇ͓lɁ|

          device         /dev/sdh1
          spare-disk     0

  ȂǂƂ킯łB

  chunk-size  32 KB ƂĺÃTCY̕ʂ̃t@CVXê
  ߂̃ftHgƂĂ͓K؂Ȓlł傤BL raidtab Őݒ肳ꂽA
  C̃TCY 6 ~ 6 GB = 36 GB ƂȂ܂i܂ (N - 1) * S = (7 -
  1) * 6 = 36 ĂƂłjBt@CVXe ext2 ŃubNETCY
   4 KB Ƃ܂Bt@CVXeɑ傫Aɑ傫t@
  CeȂAAC chunk-size ƃt@CVXẽubNT
  CY̗ςĂ݂Ɨǂł傤B

  Aׂ͏[ł傤Braidtab ݒ肵܂AČ
  ܂傤Bȉ̃R}hł݂܂B

    mkraid /dev/md0

  N邩ĂB܂΃AC̍č\zJn邽߁A
  fBXN͖җɓn߂܂BNĂ̂ /proc/mdstat 
  ĂB

  foCX̍쐬܂΁Ač\zvZX̎n܂łBč\ẑ
  tF[Ył́AAC͂܂SƂ͂܂񂪁ASɋ@\Ă
  BtH[}bgł܂AʂɎgƂł܂ifoC
  X̏Ⴕ炢܂jB

  foCXtH[}bgO ``mke2fs ̂߂̃IvV'' ZNV
  ĂB

  RAID foCX삵Ă΁A~ĊĴɈȉ̃R}hg
  Ƃł܂B

    raidstop /dev/md0

  邢

    raidstart /dev/md0

  ݒt@Cɓĉu[gA
  ɓǂݐiŁAo@\gł傤B

  4.7.  The Persistent Superblock

  ÂǂuGood Old Daysv(TM)ł́Araidtools  /etc/raidtab 
  ݍŃACĂ܂B /etc/raidtab t@C
  ݂t@CVXe}EgĂ邱ƂOƂȂ
  BRAID u[gȂǂƂꍇ́A͂낵Ȃł
  B

  X RAID foCX̃t@CVXe}EgƂ́AÂAv
  [`͏XGłBʏ̂悤 /etc/fstab ɏĂΗǂ̂ł
  ȂAXNvgŃ}EgȂ΂ȂȂ̂łB

  persistent superblock ̖͂Ă܂B/etc/raidtab
   persistent-superblock IvVtŃACƁA
  ȃX[p[ubNACɎQĂSẴfBXN̐擪ɏ
  ܂܂BɂJ[ĺARAIDfoCX̍\𒼐ڃfBXN
  ǂ߂悤ɂȂ܂Bʂ̍\t@C炢łǂ߂킯
  ܂B

  ł /etc/raidtab t@C͂̂܂܂ɂĂ܂傤BŃAC
  \zۂɕKvɂȂ邩܂B

  VXẽu[g RAID foCXo΁Apersistent
  superblock ͕K{łBɂĂ͎oZNVŏqׂ邱Ƃ
  ܂B

  i󒍁Fpersistent ƂP͎ňƁAłȁAAs
  f́AƌӖ`ełB܂ꂪv܂ł
  ŁAp\L̂܂܂ɂĂ܂j

  4.8.  Chunk TCY

  chunk-sizeɂĐ邱Ƃ͉lł傤B̃fBXNɑ
  āASɓɏނƂ͂ł܂B2 ̃fBXN 1 o
  Cg̃f[^ƂƁAꂼ̃fBXN 4 rbg
  Kv܂Bۂɂ͋Ԗڂ̃rbg̓fBXN 0 ցAԖڂ
  fBXN 1 ւƏKv܂An[hEFA͂ȂƂT|[
  gĂ͂܂B̑ Chunk TCYݒ肵܂B̓fo
  CXɏނƂłŏ́uAg~bNȁvf[^ʂƂĒ`
  ܂Bi󒍁FChunk = u܂vƂł󂹂Ηǂł傤jfBXN
  2  RAID-0 ̃P[XŁA4 KB  Chunk TCY ɂ 16 KB ̏z
  肷ƁA1 Ԗڂ 3 Ԗڂ Chunk ͍ŏ̃fBXNցA2 Ԗڂ 4 Ԗ
   Chunk ͑̃fBXNɏ܂邱ƂɂȂ܂B̂悤ɑ
  ݂̏ɑ΂ẮAȂ傫 Chunk w肷邱ƂɂăI[o
  [wbh点邩܂񂪁At@C̑ACł
  Chunk TCYǂ܂B

  Chunk TCY̓jA[hSĂ RAID xŎw肷邱Ƃł
  ܂B

  œK̃ptH[}X߂ȂAAC̃t@CVXẽubN
  TCYƓlɁAȒlł̎KvƂȂł傤B

  /etc/raidtab  chunk-size IvVɑ΂́ALoCgP
   chunk TCYw肵܂Bu4v́u4 KBvӖ邱ƂɂȂ܂B
  4.8.1.  RAID-0

  f[^̓AC̃fBXNɁuقƂǁvɏ܂܂Bۂɂ
  chunk-size oCg̃f[^AefBXNɏ킯łB

  4 KB  Chunk TCYw肵 3 ̃fBXN 16 KB 
  ARAID-0 VXeł̓fBXN 0, 1, 2  4 KB Ac 4 KB fB
  XN 0 ɏƂɂȂ܂B

  32 KB  chunk-size ͑啔̃ACœK؂Ȓlł傤AœK̒l̓h
  Cu̐t@CVXe̓eȂ̐FXȗvɔɈˑ
  Bō̃ptH[}X𓾂邽߂ɂ͎Ė͍Kv
  傤B

  4.8.2.  RAID-1

  ݂ɂĂ chunk-size ̓ACɉe܂BSẴf[^͂
  ɂSẴfBXNɏȂ΂ȂȂłBǂݍ݂
  ꍇAchunk-size ŃAC̃fBXNAIɂǂꂭ炢̃f[^
  ނw肵܂BAC̑SẴANeBuȃfBXN
  ̂ŁARAID-0 ̂悤ɕɓǂݍ߂킯łB

  4.8.3.  RAID-4

  RAID-4 ACւ̏ݎɂ́ApeBfBXNŃpeBX
  VȂ΂Ȃ܂Bchunk-size ̓peBubÑTCYƂȂ
  ܂BRAID-4 AC 1 oCgƂƁAN-1 ̃fBXN
   chunk-size oCg̃f[^ǂݍ݃peBvZAchunk-size
  oCg̃f[^peBfBXNɏ邱ƂɂȂ܂B

  RAID-0 ̏ꍇƓlAchunk-size ͓ǂݍݐ\ɉe܂BRAID-4 
  ̓ǂݍݕ͂قړłB

  4.8.4.  RAID-5

  RAID-5 ł́Achunk-size  RAID-4 ̏ꍇƊSɓӖ܂B

  RAID-5 ̂߂̍I chunk-size  128 KB łA̂悤Ɏ
  Ė͍܂ˁB

  ܂ ``mke2fs ̂߂̃IvV'' ZNVĂB
  RAID-5 ̐\ɉeyڂ܂B

  4.9.  mke2fŝ߂̃IvV

  mke2fs  RAID-4  raid-5 ̃foCXtH[}bg鎞ɗpł
  AʂȃIvV܂B-R stride=nn IvVɂ
  āAmke2fs  RAID foCX ext2 ̓ȃf[^\܂u
  Ƃł܂B

  chunk-size 32 KB ȂA 32 KB ̘Af[^ 1 ̃fBXN
  ̏ɒu܂B4 KB ̃ubNTCY ext2 t@CVXe\z
  Ȃ΁A1 ̃AC Chunk̒ 8 ̃t@CVXeub
  NƗł܂Bt@CVXe쐬鎞 mke2fs [eB
  eBɂ̏nƂł܂B

    mke2fs -b 4096 -R stride=8 /dev/md0

  RAID-{4,5}̃ptH[}X͂̃IvVɔɉe܂Bstride
  IvV RAID x̏ꍇɂǂ̂悤ȉeyڂ̊mM
  ܂BNɊւ񂪂Ύ܂őĂB

  ext2fs ̃ubNTCÝAt@CVXẽptH[}Xɔɉe
  ܂BSKoCgȏ̂ǂȃt@CVXełAubNT
  CY 4 KB ɂׂłBt@CuȂʂł

  4.10.  o

  óAJ[lu[gɕʂ̃p[eBV̌oARAIDfo
  CXIɌoł悤ɂ܂B

  ɂ͕KvȂ̂܂B

  1. J[lɎoT|[gKvł̂ŁA`FbN܂B

  2. persistent-superblock g RAID foCX쐬܂B

  3. RAID ŎgfoCX̃p[eBV^CvA0xFDifdiskg
     ă^CvufdvɂjɃZbg܂B

  NOTE: p[eBV^CvςOɁARAID ĂȂƂmF
  ĂBfoCX~߂ɂ raidstop /dev/md0 gĂ
  B

  L 1, 2, 3 ݒ肷Ύo̐ݒ͏IłBu[gĂ݂
  BVXeオƂAcat /proc/mdstat  RAID 
  lq킩܂B

  u[g̊ԁÂ悤Ȋ̃bZ[W\܂|

   Oct 22 00:51:59 malthe kernel: SCSI device sdg: hdwr sector= 512
    bytes. Sectors= 12657717 [6180 MB] [6.2 GB]
   Oct 22 00:51:59 malthe kernel: Partition check:
   Oct 22 00:51:59 malthe kernel:  sda: sda1 sda2 sda3 sda4
   Oct 22 00:51:59 malthe kernel:  sdb: sdb1 sdb2
   Oct 22 00:51:59 malthe kernel:  sdc: sdc1 sdc2
   Oct 22 00:51:59 malthe kernel:  sdd: sdd1 sdd2
   Oct 22 00:51:59 malthe kernel:  sde: sde1 sde2
   Oct 22 00:51:59 malthe kernel:  sdf: sdf1 sdf2
   Oct 22 00:51:59 malthe kernel:  sdg: sdg1 sdg2
   Oct 22 00:51:59 malthe kernel: autodetecting RAID arrays
   Oct 22 00:51:59 malthe kernel: (read) sdb1's sb offset: 6199872
   Oct 22 00:51:59 malthe kernel: bind<sdb1,1>
   Oct 22 00:51:59 malthe kernel: (read) sdc1's sb offset: 6199872
   Oct 22 00:51:59 malthe kernel: bind<sdc1,2>
   Oct 22 00:51:59 malthe kernel: (read) sdd1's sb offset: 6199872
   Oct 22 00:51:59 malthe kernel: bind<sdd1,3>
   Oct 22 00:51:59 malthe kernel: (read) sde1's sb offset: 6199872
   Oct 22 00:51:59 malthe kernel: bind<sde1,4>
   Oct 22 00:51:59 malthe kernel: (read) sdf1's sb offset: 6205376
   Oct 22 00:51:59 malthe kernel: bind<sdf1,5>
   Oct 22 00:51:59 malthe kernel: (read) sdg1's sb offset: 6205376
   Oct 22 00:51:59 malthe kernel: bind<sdg1,6>
   Oct 22 00:51:59 malthe kernel: autorunning md0
   Oct 22 00:51:59 malthe kernel: running: <sdg1><sdf1><sde1><sdd1><sdc1><sdb1>
   Oct 22 00:51:59 malthe kernel: now!
   Oct 22 00:51:59 malthe kernel: md: md0: raid array is not clean --
    starting background reconstruction

  ͐ɃVbg_EȂiႦ΃}VNbV
  jRAID-5 AC̎oɏo͂ꂽ̂łBč\z͎IɎn
  ܂܂B̃foCX̏Ԃ̂܂܃}EgĂSɈSłB
  ̂č\z͓ߓIŁASẴf[^ (consistent) Ă邩
  łiѐȂ̂̓peB񂾂łAfoCX̏Ⴗ܂ł
  Kv܂jB

  nfoCX̓Vbg_Eɂ~܂BXN
  vgɂĐSzKv͂܂B/dev/md foCX /dev/sd 
  /dev/hd foCXƓ悤Ɏg܂B

  ȒPłˁB

  raidstart/raidstop R}h̎gm邽߂ɏXNvg`
  Ă݂̂ł傤B͕WI RedHat ̏XNvg
  ́AĂ܂܂Ă܂B炪ĝ͋ RAID ̂߂Ȃ
  ŁAot̐V RAID ɂ͗pȂ܂B̍s͍Ă܂
  ܂傤AłׂĂ܂܂B

  4.11.  RAID Ńu[g

  RAID foCX̃[gt@CVXeɃVXeZbgAbv
  ͂̕@܂B̂ƂARedHat Linux 6.1 ̃OtBJ
  ECXg[ARAID foCXւ̒ڃCXg[񋟂Ă
  ɂ܂BłA肽ΏЂ˂Kv܂A
  Ɖ\ȂƂłB

  ŐV̌ lilo fBXgr[V(o[W 21 )ł RAID fo
  CX܂Ału[gɃJ[l RAID foCX烍[h
  邱Ƃ͂ł܂B̃o[WgĂꍇ /boot t@C
  VXe RAID łȂfoCX̏ɒuȂ΂ȂȂƂɂȂ
  BVXemɃu[g@ RAID foCXׂ̂ẴhCu
  ɓ悤 /boot p[eBVABIOS pł(ႦΈ
  Ԗڂ)hCuɃf[^[h悤ɐݒ肷邱ƂłB
  ߂ɂ̓VXě̏ႵfBXNu[g悤ƂĂ͂܂
  B

  redhat 6.1 ł́ARAID-1  /boot Ƃł lilo 21 ւ̃pb`
  pł悤ɂȂ܂B̃xł͓܂AӂĂ
  BRAID-1 (~[O) T|[g RAID xłB
  pb` (lilo.raid1) ́Aredhat ̂ǂ̃~[ł
  dist/redhat-6.1/SRPMS/SRPMS/lilo-0.21-10.src.rpm Ōł傤B
  ̃pb`Kpꂽ LILO ́A lilo.conf ̒ boot=/dev/md0 Ƃ
  ߂󂯕t悤ɂȂA~[\ǂ̃fBXNłu
  [gł悤ɂĂ܂B

  VXemɃu[g邱Ƃł̕@́ASẴZbg
  AbvI_Ńu[gEtbs[邱ƂłB/boot t@C
  VXeڂfBXNłAłtbs[u[g邱
  Ƃł܂B

  4.12.  RAID ̃[gt@CVXe

  VXe RAID Ńu[gɂ́A[gt@CVXei / j
  RAID foCXŃ}EgȂ΂Ȃ܂B 2 
  @ȉɎ܂B݂̃fBXgr[ViȂƂm
  Ăj RAID foCXɃCXg[邱ƂT|[gĂ܂
  A@ƂĂ͕ʂ(RAID ł͂Ȃ)p[eBVɃCXg[
  sȂACXg[I RAID łȂ[gt@CVXe
  eV RAID foCXɈړ܂B

  4.12.1.  @ 1

  ̕@ł́Aꂩ\悤ƂĂ RAID Ƃ͕ʂɗ\̃fBXN
  pӂȀɃVXeCXg[܂B

  o  ŏ́Aʂ̃VXe\fBXNɃCXg[܂B

  o  J[lApb`Araidtools pӂAV RAID ΉJ[lŃV
     Xeu[g܂BRAID T|[g̓W[Ƃă[ĥ
     ȂAJ[lɑgݍ݂܂B

  o  ɁA[gt@CVXeƂĎg\ RAID ݒA\zs
     Ȃ܂B͂̂̕ǂɋLqĂ悤ɁAʂ̕
     @ōsȂ܂B

  o  RAID u[gɂƓ삷邱ƂmF邽߂ɃVXeu
     [gĂ݂܂B͂łB

  o  VACɃt@CVXeimke2fs gjA/mnt/newroot
     Ƀ}Eg܂B

  o  V[gt@CVXeiACjɁÃ݂[gt@CVX
     ei\fBXNj̓eRs[܂B낢@͂܂
     AƂ΁Â悤ɂ܂B

      cd /
      find . -xdev | cpio -pm /mnt/newroot

  o  [gt@CVXeƂĐfoCXg߂
     /mnt/newroot/etc/fstab t@CC܂i/dev/md? [gfo
     CXɂ܂jB

  o  ݂ /boot t@CVXeA}EgāȂɃu[g
     foCX /mnt/newroot/boot Ƀ}Eg܂B͎̃Xebv
     LILO ܂点邽߂ɕKvłB

  o  foCXw悤 /mnt/newroot/etc/lilo.conf C
     Bu[gfoCX͂܂ʂ̃fBXNiRAID łȂfoCXjłȂ
     ΂Ȃ܂񂪁A[gfoCX͐V RAID ĂKv
     ܂B̍ƂIA

      lilo -r /mnt/newroot

  o  VXeċN܂AׂĂ\ʂ藧オ̂mFĂ
      :)

  ̍Ƃ IDE fBXNłĂȂ΁ABIOS őSẴfBXN
  uauto-detectv^Cvɐݒ肵ĂB BIOS fBXN
  1Ȃ悤Ȏł}V̓u[g邱Ƃłł
  B

  4.12.2.  @ 2

  ̕@́Afailed-disk ߂̎g raidtools ƃpb`gKv
  ܂B 2.2.10 ȍ~ׂ̂ẴJ[l̂߂ raidtools ƃpb
  `ƂȂł傤B

  ̕@ RAID x 1 ȏ݂̂Ŏgp邱Ƃł܂BӐ}IɌ
  ƃ}[NꂽfBXNɃVXeCXg[AꂩfO[
  h[hő邱ƂɂȂ RAID ɃRs[AŌɕsvɂȂuCXg
  [fBXNv̌ÂVXe RAID \zAfO[h[
  hœ삳܂B

  i󒍁FfO[h[h "degraded mode" Ƃ̂́A璷̂ RAID
  ̈ꕔ̏ႵĂ邪Af[^̊S͕ۂĂԂ̂Ƃłj

  o  ŏ́Aʂ̃VXe 1 ̃fBXNi RAID ɑgݍ܂
     jɃCXg[܂B̃fBXNi܂̓p[eBVj
     ł̂łȂƂdvłBȂƌ RAID ɉ邱
     ƂłȂȂ܂I

  o  J[lApb`Araidtools Ȃǂ肵Ă܂傤BKv RAID
     T|[ggݍ񂾐VJ[lŁAVXeu[g悤ɂ
     ܂B

  o  raidtab t@C̃[gfoCX failed-disk Ƃ RAID Zbg
     Abv܂Braidtab ɂ failed-disk ŏ̃fBXNƂĒu
     ͂܂BRAID n鎞ɖɂȂ܂BRAID \zA
     t@CVXe܂B

  o  u[gĂ݂āA\ʂ RAID オ邱ƂmF܂B

  o  ÕZNVɂċLqĂ̂Ɠl̂ŁAVXet@
     CRs[āA[gfoCXƂ RAID g悤ɃVXe
     Đݒ肵܂B

  o  VXe RAID 炤܂u[gAraidtab t@CC
     Afailed-disk ƂĂfBXN𕁒ʂ RAID fBXNƂ
     B raidhotadd R}hł̃fBXN RAID ɑgݍ݂܂B

  o  fO[h[hȂi܂ƂȁjRAID u[g邱Ƃł
     VXełĂ͂łB

  4.13.  RAID Ńu[gVXe

  [gt@CVXe}Eg邱ƂłJ[l̂߂ɁA[
  gt@CVXeufoCX̑SẴT|[g̓J[lɑgݍ
  ܂ĂȂ΂Ȃ܂BāARAID foCXŃ[gt@C
  VXe}Eg邽߂ɂ́AJ[l RAID T|[ggݍ܂
  ĂȂ΂Ȃ܂B

  J[l RAID foCX邱ƂmF镁ʂ̕@́APɑS
  ̕Kv RAID T|[ggݍŃJ[lRpC邱Ƃ
  BRAID T|[g[_uW[ł͂ȂAJ[lɑg݂
  邱ƂmFĂBJ[l̓W[̃[h([gt@
  CVXe)[gt@CVXe}EgOɍsȂ
  ͂ł܂B

   RedHat 6.0 ̓W[ƂĐV RAID T|[gJ[
  l܂܂Ă܂Ał͂ǂ̂悤ɕW RedHat 6.0 J[l
   RAID ォVXeu[g邩ɂċLq܂B

  4.13.1.  W[gp RAID Ńu[g

  u[g邽߂ɂ́ALILO  RAM fBXNg悤ɎwKv
  ܂Bu[gp[eBV}EĝɕKvȑSẴJ[l
  W[܂ł RAM fBXNvƂ mkinitrd R}h
  g܂B

  ̂悤ɂ܂B

   mkinitrd --with=<module> <ramdisk name> <kernel>

  ̓Iɂ́Â悤ɂȂ܂B

   mkinitrd --with=raid5 raid-ramdisk 2.2.5-22

  ɂAJ[l[gfoCX}Eg邽߂ɕKv RAID 
  W[u[gɑ݂邱Ƃۏ؂܂B

  4.14.  

  āAāAāAғĂ RAID ̈ꕔłfBXÑp[
  eBV̐؂蒼Ă͂܂BRAID ̈ꕔłfBXN
  p[eBVe[uύXKv̂ȂAŏɃAC~߂
  B̌Ƀp[eBV؂蒼̂łB

  ɑ̃fBXNoXɕt邱Ƃ͊ȒPłBʂ Fast-Wide
  SCSI oX 10 MB/s T|[gł܂A͍ł͂قƂǂ̃fB
  XNPƂł̐\ȂlłBȃoXɃfBXN 6 u
  ҂ptH[}X͏o܂B

  SCSI oXoX̃fBXN̔\͂łقƂǖtɂȂ悤ȂASCSI R
  g[𕡐ɂ邱ƂA\̗B̕@ƂȂ܂B2 ̌
   SCSI fBXNi1̃Rg[ 2̃fBXN𑖂点邱Ƃ
  ȂājŁA2  2940 gĂ\͌܂B

  persistent-superblock IvVYꂽꍇA~͂܂N
  ȂȂ邩܂Braidtab ŃIvV𐳂ZbgȂ
  āAACč\ĂB

  RAID-5 ŃfBXNOAđ}ɍč\zsꍇA
  raidtab ̒̃foCX̏̂߂܂Bŏ́udevice...v
  Ɓuraid-disk...ṽyA raidtab t@C̒̃ACɊւLq
  ֓̕Ă݂ĂB

  5.  eXg

  tH[ggX𓾂邽߂ RAID g\肪A܂ꂪ{
  ɓ삷邩ǂ𒲂ׂ邽߂ɐݒeXg܂ˁB
  ́Aǂ̂悤ɃfBXN̏V~[V悢ł傤H

  ͂茾āA퓮삵ĂfBXNŌ̏V~[V
  ͖ȘbłBhCu񂾂牽N邩m邱Ƃ͂ł܂B
  dCIɃoXāAoX̑SẴhCuANZXs\ɂ邩
  ܂B͂܂łƂNƂ͕Ƃ
  ܂BhCu SCSI/IDE CɓǍ݁Ẽ݂G[񍐂邩
  ܂BĂ RAID C͏󋵂fɈƂł
  ̂łB܁A͊ҒʂɓĂƎv܂B

  5.1.  hCǔ̏V~[V

  hCȕV~[V̂ȂAhCuOƂłB
  ̏ꍇ͕Kd𗎂ƂĂɂĂBfBXN炵ăf[
  ^c邩ǂɂĒׂȂ΁AVXe~ăfBXN
  𔲂AċNΗǂ̂łB

  syslog  /proc/mdstat  RAID ǂȂĂ邩܂B܂
  Ă܂H
  fBXN̏؂ɂ́ARAID-{1,4,5} 𑖂点ĂȂ΂Ȃ܂
  BfoCXȂƂAjA[h RAID-0 ͊Sɔj]
  B

  fBXNĐڑidĂԂŐڑ̂YꂸɁj
  ꍇ́Araidhotadd ߂ōĂсuVvfoCX RAID ɉ邱
  Ƃł܂B

  5.2.  f[^̔jV~[V

  RAIDin[hł\tgłjł́AݎɃG[ԂȂƐ
  ݂Ȃ܂BāAfBXNG[ԂƂȂf[^ꂽ
  AǁAf[^͔j󂳂킯łB񂱂͋N肻ɂȂ
  ƂłAFł͂܂BČʂƂăt@CVXej
  邱ƂɂȂ̂łB

  RAID ̓fBÃf[^jɑ΂ی͑z肵Ă܂B
   RAID VXeǂ̂悤ƂāAfBXNɌ̈ӂɕsȃf
  [^ށiႦ dd gāj悤ȂƂ͈Ӗ̂ȂƂ
  BRAID C͔joȂł傤iRAID ̃X[p[ubN
  j󂵂ȂjARAID foCX̃t@CVXe͔j󂳂܂B

  ͓R̂ƂłBRAID ̓f[^̊Sɑ΂ۏ؂ł͂܂
  BfBXN񂾎Ƀf[^Ă̂łi RAID 
  x 1 ȏjB

  6.  č\z

   HOWTO ǂݐiłȂAfO[h RAID ̍č\zɂāA
  łɂȂ悢ACfA͂łBȒPɂ܂Ƃ߂Ɓ|

  o  VXe̓d𗎂Ƃ

  o  ꂽfBXN

  o  VXe̓dē

  o  ACɃfBXNʂɑ}邽߂ raidhotadd /dev/mdX
     /dev/sdX R}hgp

  o  č\zĂԂ̓R[q[łǂ

     ƂƂɂȂ܂傤B

  āA璷̃fBXN̏ႵƂɂ RAID gȂ
  ƂԂ́AʂɋN肤邱ƂłB̃fBXNoX
  ɂȂĂƁAۂɋN邱Ƃ܂B1̃fBXNNb
  VoXɉeyڂ̂łB̃fBXNȏԂłoX_E
  Ă̂ RAID CɓBłȀƃ}[N̂łB1
  ̃fBXN璷Ƃ RAID-5 ̏ 2ȏ̃fBXN̏͒vI
  B

  ȉ̃ZNV Martin Bene ɐĂꂽƂłāAOq
  ̋낵ViỈ񕜕@Lq܂Bɂ /etc/raidtab 
  failed-disk ̋LqKv܂̂ŁAJ[l 2.2.10 ȍ~łȂ
  Ɠ삵܂B

  6.1.  fBXŇ̏Ⴉ̉

  ViÍAȉ̒ʂłB

  o  Rg[ŁA 2 ̃fBXNItCɂȂ

  o  1 ̃fBXNʂƁAscsi oXׂ̂ẴfBXNFȂ
     Ȃ

  o  P[u͂DDD

     vɁ| тыN镡fBXN̈ꎞIȌ̏ɂ RAID X
     [p[ubN sync ܂ȂȂA͂ RAID AC
     łȂȂԂłB

  cꂽ́Amkraid --force ɂ RAID X[p[ubN
  ƂłB

  ꂪ܂삷邽߂ɂ͍ŐV /etc/raidtab KvŁAIWi
  ҂}b`foCXƏȂƂ܂܂B

  ACn悤Ƃ syslog ƁAeX[p[ubÑCx
  gJEg܂BʏAłႢCxgJEg̃fBXNi
  ܂łẤjĂ̂xXgłB

  failed-disk Ȃ mkraid ƃJoXbhɋNAp
  eBubN̍č\zn܂܂B|ܕKvȂ̂ȂłˁB

  failed-disk ȂAmɂǂ̃fBXNANeBuɂɂ
  w肷邱ƂłA炭őP̌ʂ̂߂ɈقȂgݍ킹
  ݂邱Ƃł܂B̎菇Ԃ́At@CVXe̓[hI
  [Ń}Eg悤ɂׂłB̕@ŁA̒mĂ鏭ȂƂ
  2 l͂܂܂B

  7.  ptH[}X

  ̃ZNVł Software RAID gĂ錻̃VXeA
  ̃x`}[NׂĂ݂܂B

  x`}[N 킢 vOŁA}V̕ 2 {ȏ
  TCỸt@Cg܂B

  x`}[N 1 ̑傫ȃt@C̓o̓ohv邾
  BK͂ read/write ɂő I/O X[vbgɋ
  ΁AmĂ鉿l̂f炵̂łB̂悤Ȑ̓A
  Cj[XXv[AEFuT[oȂApꂽꍇɂǂ̒x
  ̃ptH[}Xo邾낤ɂẮA܂ɗȂ̂
  Bx`}[N̐́ulHIȁvvOsʂłƂ
  ƂɗӂׂłB̂قƂǂ̃vOƓ悤ȓ
  ̂ł͂Ȃ߁A̐͌̂ɂ͗ǂǂA̐E
  ͓ƂĎĝł͂܂B

  ̂ƂAg̃}V̌ʂłB\́|

  o  fA Pentium Pro 150 MHz

  o  256 MB RAM (60 MHz EDO)

  o  IBM UltraStar 9ES 4.5 GB(SCSI U2W) ~ 3

  o  Adaptec 2940U2W

  o  IBM UltraStar 9ES 4.5 GB(SCSI UW) ~ 1

  o  Adaptec 2940 UW

  o  Kernel 2.2.7 { RAID pb`

  3 U2W fBXN U2W Rg[ɂԂ牺AUW fBXN UW R
  g[ɂԂ牺Ă܂B

  ̃VXeł RAID gp̔@ɂ炸A30 MB/s ȏ SCSI o
  XɋɒʂƂ͕s\Ȃ悤łB̐ɂƁAVXe
  Â̂Ńoh SCSI Rg[̔\͂𐧌Ă悤
  B

  7.1.  RAID-0

  Read ͘AubN̓͂łAWrite ͘AubN̏o͂
  Bt@CTCY͑SẴeXg 1 GB łBeXg̓VO[U
  [[hōs܂BSCSI hCo TCQiTagged Command Queueingj
  gȂݒɂ܂B

  |Chunk size  |  Block size  |  Read KB/s  |  Write KB/s  |
  |            |              |             |              |
  |4k          |  1k          |  19712      |  18035       |
  |4k          |  4k          |  34048      |  27061       |
  |8k          |  1k          |  19301      |  18091       |
  |8k          |  4k          |  33920      |  27118       |
  |16k         |  1k          |  19330      |  18179       |
  |16k         |  2k          |  28161      |  23682       |
  |16k         |  4k          |  33990      |  27229       |
  |32k         |  1k          |  19251      |  18194       |
  |32k         |  4k          |  34071      |  26976       |

  LARAID chunk-size ςĂ\ɑ傫ȍ͏oȂ悤łB
   ext2fs ubNTCY͉\Ȍ傫ǂ悤łBIA-32 
   4 KB łiႦ΃y[WTCYȂǁjB

  7.2.  TCQ ɂ RAID-0

  x SCSI hCoATCQiTagged Command Queueingjg悤ɐݒ
  AL[̐[ 8 ƂĂ܂BȊO͑OƓłB

  |Chunk size  |  Block size  |  Read KB/s  |  Write KB/s  |
  |            |              |             |              |
  |32k         |  4k          |  33617      |  27215       |

  ȏ̃eXg͂Ă܂BTCQ ɂď\킸Ɍサ܂
  AŜƂĂ͑債Ⴂ͂Ȃƌł傤B

  7.3.  RAID-5

  AC RAID-5 [hō\AlȃeXgsȂ܂B

  |Chunk size  |  Block size  |  Read KB/s  |  Write KB/s  |
  |            |              |             |              |
  |8k          |  1k          |  11090      |  6874        |
  |8k          |  4k          |  13474      |  12229       |
  |32k         |  1k          |  11442      |  8291        |
  |32k         |  2k          |  16089      |  10926       |
  |32k         |  4k          |  18724      |  12627       |

  chunk-size ƃubNTCY̗ۂ̍悤łB

  7.4.  RAID-10

  RAID-10 ́u~[XgCvvA邢 2  RAID-0 AC
  RAID-1 ACłBchunk-size  RAID-1 AC 2  RAID-0 AC
   chunk-size łBɈӖ̂ݒ肾Ǝv܂Achunk-size 
  ςꍇɂǂȂ邩ƂeXg͂܂łB

  |Chunk size  |  Block size  |  Read KB/s  |  Write KB/s  |
  |            |              |             |              |
  |32k         |  1k          |  13753      |  11580       |
  |32k         |  4k          |  23432      |  22249       |

  ȏ̃eXg͂Ă܂Bt@CTCY 900 MB łB 4
  ̃p[eBV͂ꂼ 500 MB ŁA̐ݒi2 1000 MB ̃A
  C RAID-1jł 1 G ̃t@Ĉ߂̃Xy[XȂ̂ł
  B

  8.  NWbg

  ȉ̐lXA̍̕쐬ɍvĂ܂B

  o  Ingo Molnar

  o  Jim Warren

  o  Louis Mandelstam

  o  Allan Noah

  o  Yasunori Taniike

  o  Martin Bene

  o  The Linux-RAID mailing list people

  o  Yꂿ́A߂Ȃ :)

  AāA܂璘҂܂őĂBꂪA HOWTO
  PłB̕@łB

  󒍁Fȉ̐lXA{ɂĎwEAAhoCX܂B
  ɁA삳ɂ͓AJF ւ̒pďoĂ܂B肪
  Ƃ܂B

  o  mAsahilbg

  o  L

