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Ingredientes:

* Tambien conocido como Advanced Format. Provoca, si la herramienta no los maneja bien, particiones no alineadas

Nota He ido infinidad de veces adelante y atrás en el proceso, por lo que resumo los pasos realizados.

1. (Netinst) Borro todas las particiones

2. (Netinst) Creo las dos particiones en cada disco (/ y swap). Se me olvida marcar / como bootable

3. (Gparted) Ejecuto fdisk. Las particiones NO están alineadas.

3.1 (Gparted / fdisk ) Borro y creo la partición #2 en cada disco

3.2 (Gparted / gparted ) Creo una nueva partición dentro de #2 (es la #5) y la formateo a swap (en cada disco).

3.3 (Gparted / fdisk ) Ahora SI están alineadas las particiones

4. (Netinst) Marco las pariciones / y swap en cada disco como parte de RAID. Marco la / como bootable

5. (Netinst) Configuro los 2 RAID 1, uno para las particiones / (sda1 y sdb1) y otro para las swap (sda5 y sdb5)

6. Al arrancar veo que de nuevo las particiones NO están alineadas

6.1 Ejecuto parted y las elimino/creo de nuevo. Resumen:

Number  Start        End          Size         Type      File system     Flags
 1      2048s        1921824767s  1921822720s  primary   ext3            boot, raid
 2      1921824768s  1953525160s  31700393s    extended                  lba
 5      1921826816s  1953525160s  31698345s    logical   linux-swap(v1)  raid

7. Instalo grub en el disco 2:

sudo grub-install /dev/sdb

mdadm --create --verbose /dev/md0 --raid-devices=4 --level=raid5 /dev/sda /dev/sdb /dev/sdc /dev/sdd

Formateamos el RAID

mkfs.ext3 /dev/md0

Instalación Raid en Debian

http://www.debian-administration.org/articles/512

http://www.esdebian.org/forum/viewtopic.php?forum=12&showtopic=103488

One thing should be added to this nice article in case this installation is being done on brand new pristine disks.

If Grub is being installed on the RAID1 boot sector rather than MBR and you are on x86 or x86_64, the debian installer will probably prompt you about having an MBR installed (as this is required for the BIOS to initially access the disk).

At this step you can only pick from one of the physical devices and not the RAID partitions. So the MBR should be manually installed on the other disks as a post installation task to ensure that no disk is being left MBRless and so unusable by the BIOS.

This should be true with PATA hardware and is something i went through when performing RAID sanity tests after an etch install (a year ago or so).

Most of the time i have no specific requirements for an MBR, so i usually tend to install the bootloader on the MBR and then duplicate it by hand on the other disks.

For the record, here's how I do the MBR replication:

# grub –no-floppy

device (hd0) /dev/sda
root (hd0,0)
setup (hd0)

device (hd0) /dev/sdb
root (hd0,0)
setup (hd0)

device (hd0) /dev/sdc
root (hd0,0)
setup (hd0)

… and so on.

Notes: * –no-floppy speeds up grub's loading * the 'device' trick insures that the 2nd stage and the kernel are loaded from the same disk as the MBR, provides some independence from the BIOS settings (i've seen some voodoo cases where this was required) * to be noted that after the first disk, the grub-shell history is of great use: 3xup,bksp,b, enter, 3xup, enter, 3xup, enter , and so on ;) * take great care that the raid1 is in sync, to insure that all the required files are in their final position on disk * thanks to grub's architecture, this only has to be done when upgrading grub or when changing a disk, not on every reconfiguration or kernel upgrade.

Mostramos los discos que hay

clear; cat /proc/mdstat

  Personalities : [raid1] [raid6] [raid5] [raid4]
  md1 : active raid5 sda2[0] sdc2[2] sdb2[1]
      957232896 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

mdadm --detail /dev/md1

  /dev/md1:
        Version : 00.90.03
  Creation Time : Thu Oct 25 21:16:03 2007
     Raid Level : raid5
     Array Size : 957232896 (912.89 GiB 980.21 GB)
    Device Size : 478616448 (456.44 GiB 490.10 GB)
   Raid Devices : 3
  Total Devices : 3
  Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Oct 26 11:48:40 2007
          State : clean
  Active Devices : 3
  Working Devices : 3
  Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 141d4151:1b6badaa:ac063430:591eaac6
         Events : 0.10

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       8       18        1      active sync   /dev/sdb2
       2       8       34        2      active sync   /dev/sdc2

Los 3 discos del RAID 5 están funcionando correctamente.

Forzamos el fallo en un disco:

mdadm --manage --set-faulty /dev/md1 /dev/sdb2

  mdadm: set /dev/sdb2 faulty in /dev/md1

cat /proc/mdstat

  Personalities : [raid1] [raid6] [raid5] [raid4]
  md1 : active raid5 sda2[0] sdc2[2] sdb2[3](F)
      957232896 blocks level 5, 64k chunk, algorithm 2 [3/2] [U_U]

clear; mdadm --detail /dev/md1

  /dev/md1:
        Version : 00.90.03
  Creation Time : Thu Oct 25 21:16:03 2007
     Raid Level : raid5
     Array Size : 957232896 (912.89 GiB 980.21 GB)
    Device Size : 478616448 (456.44 GiB 490.10 GB)
   Raid Devices : 3
  Total Devices : 3
  Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Oct 26 12:04:08 2007
          State : clean, degraded
  Active Devices : 2
  Working Devices : 2
  Failed Devices : 1
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 141d4151:1b6badaa:ac063430:591eaac6
         Events : 0.16

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       0        0        1      removed
       2       8       34        2      active sync   /dev/sdc2

       3       8       18        -      faulty spare   /dev/sdb2

En /var/log/syslog vemos las lineas:

  Oct 26 12:04:03 servidor kernel:  --- rd:3 wd:2 fd:1
  Oct 26 12:04:03 servidor kernel:  disk 0, o:1, dev:sda2
  Oct 26 12:04:03 servidor kernel:  disk 1, o:0, dev:sdb2
  Oct 26 12:04:03 servidor kernel:  disk 2, o:1, dev:sdc2
  Oct 26 12:04:03 servidor kernel: RAID5 conf printout:
  Oct 26 12:04:03 servidor kernel:  --- rd:3 wd:2 fd:1
  Oct 26 12:04:03 servidor kernel:  disk 0, o:1, dev:sda2
  Oct 26 12:04:03 servidor kernel:  disk 2, o:1, dev:sdc2
  Oct 26 12:04:03 servidor mdadm: Fail event detected on md device /dev/md1, component device /dev/sdb2

Sacamos el disco del RAID5. Se saca en caliente si no está activo en el RAID:

mdadm  /dev/md1 --remove /dev/sdb2

  mdadm: hot removed /dev/sdb2

Aparece quitado:

mdadm --detail /dev/md1

  /dev/md1:
        Version : 00.90.03
  Creation Time : Thu Oct 25 21:16:03 2007
     Raid Level : raid5
     Array Size : 957232896 (912.89 GiB 980.21 GB)
    Device Size : 478616448 (456.44 GiB 490.10 GB)
   Raid Devices : 3
  Total Devices : 2
  Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Oct 26 12:14:21 2007
          State : clean, degraded
  Active Devices : 2
  Working Devices : 2
  Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 141d4151:1b6badaa:ac063430:591eaac6
         Events : 0.62

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       0        0        1      removed
       2       8       34        2      active sync   /dev/sdc2

Lo volvemos a añadir:

mdadm  /dev/md1 -a /dev/sdb2

  mdadm: re-added /dev/sdb2

clear; mdadm --detail /dev/md1

  /dev/md1:
        Version : 00.90.03
  Creation Time : Thu Oct 25 21:16:03 2007
     Raid Level : raid5
     Array Size : 957232896 (912.89 GiB 980.21 GB)
    Device Size : 478616448 (456.44 GiB 490.10 GB)
   Raid Devices : 3
  Total Devices : 3
  Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Oct 26 12:15:12 2007
          State : active, degraded, recovering
  Active Devices : 2
  Working Devices : 3
  Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 64K

  Rebuild Status : 0% complete

           UUID : 141d4151:1b6badaa:ac063430:591eaac6
         Events : 0.65

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       3       8       18        1      spare rebuilding   /dev/sdb2
       2       8       34        2      active sync   /dev/sdc2

Si volvemos a lanzar el comando:

  Rebuild Status : 18% complete

Vemos como se está reconstruyendo el disco:

cat /proc/mdstat

  Personalities : [raid1] [raid6] [raid5] [raid4]
  md1 : active raid5 sdb2[3] sda2[0] sdc2[2]
      957232896 blocks level 5, 64k chunk, algorithm 2 [3/2] [U_U]
      [>....................]  recovery =  0.8% (3914236/478616448) finish=112.2min speed=70464K/sec

#cat /proc/mdstat

md1 : 
     active raid5 sda2[0] sdc2[2] sdb2[1]
     957232896 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU] 

md0 : 
     active raid1 sda1[0] sdc1[2]
     9767424 blocks [3/2] [U_U] 

unused devices: <none>

Añadir un disco
Si tenemos un RAID 5 con 3 discos y queremos añadir otro, primero lo añadimos.
Actualmente el RAID está así:
#cat /proc/mdstat

Personalities : [raid1] [raid6] [raid5] [raid4]
md0 : active raid1 sda1[0] sdd1[2] sdc1[1]
      9767424 blocks [3/3] [UUU]

#mdadm –detail /dev/md0
/dev/md0:

      Version : 00.90.03 \\
Creation Time : Thu Oct 25 21:15:28 2007 \\
   Raid Level : raid1 \\
   Array Size : 9767424 (9.31 GiB 10.00 GB) \\
  Device Size : 9767424 (9.31 GiB 10.00 GB) \\
 Raid Devices : 3 \\
Total Devices : 3 \\

Preferred Minor : 0

  Persistence : Superblock is persistent \\

Update Time : Sat Nov 3 15:07:36 2007

        State : clean \\

Active Devices : 3
Working Devices : 3
Failed Devices : 0

Spare Devices : 0 \\

         UUID : a912d356:3a213509:fb13e982:631824f5 \\
       Events : 0.1284

  Number   Major   Minor   RaidDevice State \\
     0       8        1        0      active sync   /dev/sda1 \\
     1       8       33        1      active sync   /dev/sdc1 \\
     2       8       49        2      active sync   /dev/sdd1

Añadimos el disco:
#mdadm /dev/md0 -a /dev/sdb1
mdadm: added /dev/sdb1

Ahora el disco aparecerà en reserva:

servidor:~# mdadm –detail /dev/md0 /dev/md0:

      Version : 00.90.03
Creation Time : Thu Oct 25 21:15:28 2007
   Raid Level : raid1
   Array Size : 9767424 (9.31 GiB 10.00 GB)
  Device Size : 9767424 (9.31 GiB 10.00 GB)
 Raid Devices : 3
Total Devices : 4

Preferred Minor : 0

  Persistence : Superblock is persistent

  Update Time : Sat Nov  3 15:12:17 2007
        State : clean

Active Devices : 3 Working Devices : 4 Failed Devices : 0

Spare Devices : 1

         UUID : a912d356:3a213509:fb13e982:631824f5
       Events : 0.1284

  Number   Major   Minor   RaidDevice State
     0       8        1        0      active sync   /dev/sda1
     1       8       33        1      active sync   /dev/sdc1
     2       8       49        2      active sync   /dev/sdd1

     3       8       17        -      spare   /dev/sdb1

Aumentamos el tamaño del RAID para que lo coja: #mdadm –grow /dev/md0 –raid-devices=4

md0 : active raid1 sdb1[4] sda1[0] sdd1[2] sdc1[1]

    9767424 blocks [4/3] [UUU_]
      resync=DELAYED

md1 : active raid5 sda2[0] sdb2[3] sdd2[2] sdc2[1]

    957232896 blocks super 0.91 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
    [>....................]  reshape =  1.4% (7020736/478616448) finish=539.3min speed=14570K/sec

Para que coja todo el tamaño del disco:

#mdadm --grow /dev/md1 --size=max

Todavía no ha cogido el filesystem todo el tamaño: #pvdisplay

1. – Physical volume —

PV Name /dev/md1

VG Name               servidor
PV Size               912.89 GB / not usable 0
Allocatable           yes (but full)
PE Size (KByte)       4096
Total PE              233699
Free PE               0
Allocated PE          233699
PV UUID               FWHDaX-piDe-3962-ThyA-xUoX-I49J-v2qOoF

Le decimos que lo coja todo:
# pvresize /dev/md1

Physical volume "/dev/md1" changed
1 physical volume(s) resized / 0 physical volume(s) not resized

servidor:~# pvdisplay

1. – Physical volume —

PV Name /dev/md1

VG Name               servidor
PV Size               1.34 TB / not usable 0
Allocatable           yes
PE Size (KByte)       4096
Total PE              350549
Free PE               116850
Allocated PE          233699
PV UUID               FWHDaX-piDe-3962-ThyA-xUoX-I49J-v2qOoF

Primero hacemos un test: #lvresize -v -d -t -L +457G /dev/servidor/servidor_home

Nos la jugamos:
#lvresize -v -d -L +457G /dev/servidor/servidor_home

  Found volume group "servidor"
  Loading servidor-servidor_home table
  Suspending servidor-servidor_home (253:3)
  Found volume group "servidor"
  Resuming servidor-servidor_home (253:3)
Logical volume servidor_home successfully resized

Una vez añadido incrementamos el tamaño online. Necesitamos el paquete ext2resize: #ext2online /dev/servidor/servidor_home

http://scotgate.org/?p=107