Dotaz: Jak dostat data z jedno disku v raid1

[Pepa]

Zdravim. Mam otazku kterou jsem povazoval za zcela trivialni, ale uz si s tim hraju druhy den a stale bez uzpechu. Mam dva disky s raid1. A co kdyz jeden selze? Po nastartovani mi to stale hlasi ze je tam system "linux raid autodetected" a nejde z nej cist. Vy nekdo jak znej jednoduse precist data? (Tedy jednoduse to zrejme nejde) tak proste jak precist data. Diky Je to na Ubuntu 12.04

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Odpovědi

[NN]

Raid 1 by mnel pri vypadku jednoho disku nabootovat do degradovaneho pole a jet dal, takze jsi to mnel zle nakonfigurovane. Pocitam ze na tom disku neni zavadec, takze budes muset do grubu a nadiktovat mu to manualne.

[Pepa]

No mozna jsem to zle nastavene mel, ale kazdopadne to fungovalo. Pocitac bootuje z jineho disku, take nabootuje OK, ale z toho disku nelze cist ani ho pripojit. Typ je "Linux raid autodetect" a kdyz ho chci pripojit tak je odpoved:

root@ubuntu:/home/ubuntu# mount -t ext4 -o ro /dev/sda2 /backup/
mount: wrong fs type, bad option, bad superblock on /dev/sda2,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

[lertimir]

Ale to nemůžeš moutovat přímo RAID oddíl. Jak již bylo napsáno nejdříve pomocí mdadm vytvořit RAID 1 pole s jedním diskem (degradované) a tím vznikne /dev/md123 - další fyzické zařízení a to se mountuje. možná ho tam už i máš.

[Pepa]

No to jsem take zkousel:

mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb1 missing
fdisk /dev/md1
Command (m for help): p

Disk /dev/md0: 70.0 GB, 70025936896 bytes
2 heads, 4 sectors/track, 17096176 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x34814bf5

    Device Boot      Start         End      Blocks   Id  System

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-17096176, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-17096176, default 17096176): 
Using default value 17096176

Command (m for help): p

Disk /dev/md0: 70.0 GB, 70025936896 bytes
2 heads, 4 sectors/track, 17096176 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x34814bf5

    Device Boot      Start         End      Blocks   Id  System
/dev/md0p1               1    17096176    68384702   83  Linux

ale kdyz jsem to zkusil pripojit tak to dopadlo zase stejne:

root@ubuntu:/home/ubuntu# mount -t ext4 -o ro /dev/md0p1 /backup/
mount: wrong fs type, bad option, bad superblock on /dev/md0p1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

[multi]

Cez mdadm --create sa vytvára nové pole. Pôvodný raid si tým možno už zabil. Na poskladanie havarovaného poľa slúži mdadm --assemble

[Milan Roubal]

chtelo by to vice informaci. Vystup prikazu

fdisk -l

cat /proc/mdstat

cat /etc/mdadm/mdadm.conf

+ vypisy z logu /var/log/messages z doby, kdy to pole behalo a ted.

[Pepa]

root@ubuntu:/home/ubuntu# fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00033ad1

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        1216     9764864   fd  Linux raid autodetect
/dev/sda2            1216        9730    68384768   fd  Linux raid autodetect

*******************

root@ubuntu:/home/ubuntu# cat /proc/mdstat
Personalities : 
unused devices: none

******************* Ten posledni soubor neexistuje. Raid jsem nastavoval behem instalace Ubuntu a ne pomoci mdadm. Ted pracuji na live CD ubuntu.

[j]

Pokud si to mel aspon castecne funkcni (nemas ten disk bootovatelnej, ale data na nem sou), tak by mel jit primontovat samostatne z libovolnyho live distra.

[camel1cz]

Ono vadí, že typ partition je RAID autodetect (FD)... pokud chceš mountit ten disk ručně z jiné instalace, tak bude třeba změnit typ partition na linux (82)...

[Pepa]

O to jsem se presne snazil pres fdisk:

fdisk /dev/sda2
Command (m for help): t
No partition is defined yet!
Command (m for help):

[Pepa]

Oprava, koukam ze jsem se snazil upravit sda2 takze ted takto:

fdisk /dev/sda
Command (m for help): p
Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1216     9764864   fd  Linux raid autodetect
/dev/sda2            1216        9730    68384768   fd  Linux raid autodetect
Command (m for help): t
Partition number (1-4): 1
Hex code (type L to list codes): 83

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00033ad1

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1216     9764864   83  Linux
/dev/sda2            1216        9730    68384768   fd  Linux raid autodetect

Tak to se povedlo, ale Zadna zmena u mount:

root@ubuntu:/home/ubuntu# mount -t ext4 /dev/sda1 /backup/
mount: wrong fs type, bad option, bad superblock on /dev/sda1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

[Jakub Veverka]

Jsou na starem disku jeste nejaka stara raid metadata?

Zjistite pomoci mdadm --examine /dev/sda2 z live distribuce

[Pepa]

root@ubuntu:/home/ubuntu# mdadm --examine /dev/sda2
/dev/sda2:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : e5cb84f0:a7c87e70:04b5dd61:64d01b73
           Name : ubuntu:1  (local to host ubuntu)
  Creation Time : Tue Oct 30 19:27:29 2012
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 136638464 (65.15 GiB 69.96 GB)
     Array Size : 136587008 (65.13 GiB 69.93 GB)
  Used Dev Size : 136587008 (65.13 GiB 69.93 GB)
    Data Offset : 131072 sectors
   Super Offset : 8 sectors
          State : active
    Device UUID : 187f41fc:584f0f1d:9264cc51:2bc4d615

    Update Time : Tue Oct 30 19:57:04 2012
       Checksum : b1d8b911 - correct
         Events : 7


    Array Slot : 1 (0, 1, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed, failed)
   Array State : uU 126 failed
root@ubuntu:/home/ubuntu# 

[pet]

mdadm --assemble /dev/md0 /dev/sda2 missing

mount -t ext4 -o ro /dev/md0 /backup/

To mdadm bude mozna chtit --force.

Pozor, nepouzivat --create nebo --build, vytvari novy raid => znici puvodni!

[Milan Roubal]

jo, puvodni pole je znicene, to je videt z

Creation Time : Tue Oct 30 19:27:29 2012

a pokud neni bitova zaloha dat, tak uz to muze byt docela strelba na slepo pokusit se ty data zachranit.

pokud bylo to --create spustene pouze na sda2, tak by jsme mohli jeste nejake dulezite udaje vycist z

mdadm --examine /dev/sda1

jak bylo to puvodni pole vytvorene? Priblizne kdy / v jake distribuci? Jde o to, zda tam puvodne nebyl napriklad raid s verzi metadat 0.90 nebo 1.0, pricemz nove live CD vytvareji automaticky metadata verze 1.2 a tim prepisuji prvnich 2 MB dat. Pak se daji data zachranit jeste tak, ze se vytvori pole s verzi metadat 0.90 a spusti se na to fsck.