Difference between revisions of "RAID"

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(Reverted edits by Ypebezimyx (Talk) to last version by 193.146.196.192)
 
Line 114: Line 114:
  fricco ~ # mdadm --manage /dev/md5 -r /dev/hdb1
  fricco ~ # mdadm --manage /dev/md5 -r /dev/hdb1
  mdadm: hot removed /dev/hdb1
  mdadm: hot removed /dev/hdb1
== reset raid information of a disk ==
mdadm --zero-superblock /dev/<disk>
== Sostituire un disco in raid1 Corrotto ==
== Sostituire un disco in raid1 Corrotto ==
* La configurazione è la seguente:
* La configurazione è la seguente:

Revision as of 12:46, 29 October 2011

Il Raid è la soluzione migliore per non rischiare di perdere tutto per colpa di discacci malfnzionanti.

  • Appunto, ho questi due discacci (Maxtor molto cattivi) li metto a specchio per:
  1. guadagnare velocità di lettura
  2. se un disco muore, l'altro farà il suo lavoro

mdadm

Gestore + comune e semplice di dispositivi RAID

comandi al volo

  • crea bitmap
mdadm /dev/md3 -Gb internal

oppure 

mdadm --grow --bitmap=internal /dev/md3
  • mdadm: set /dev/sda1 faulty in /dev/md0
mdadm /dev/md0 -f /dev/sda1
  • mdadm: hot removed /dev/sda1
mdadm /dev/md0 -r /dev/sda1
  • mdadm: hot added /dev/sda1
mdadm /dev/md0 -a /dev/sda1
  • creo un raid multipath con 4 dischi
mdadm -C /dev/md0 --level=multipath --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1
Continue creating array? yes
mdadm: array /dev/md0 started.
  • Verificare la consistenza:
echo check >> /sys/block/mdX/md/sync_action
watch -n .1 cat /proc/mdstat
  • Controllare la velocità del RAID
cat /proc/sys/dev/raid/speed_limit_max

per un massimo di 30MB/sec. 

echo "30000" > /proc/sys/dev/raid/speed_limit_max

recuperare un raid1

livecd ~ # mdadm --assemble /dev/md1 /dev/hda5 /dev/hdc5
mdadm: /dev/md1 has been started with 2 drives.
livecd ~ # cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 hda5[0] hdc5[1]
     19542976 blocks [2/2] [UU]
     bitmap: 0/150 pages [0KB], 64KB chunk
unused devices: <none>

Installare il sistema su RAID software

mknod /dev/md1 b 9 1
mknod /dev/md2 b 9 2
mknod /dev/md3 b 9 3
mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1
mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2
mdadm --create --verbose /dev/md3 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3
mdadm --detail --scan > /etc/mdadm.conf
mdadm /dev/md1 -Gb internal
mdadm /dev/md2 -Gb internal
mdadm /dev/md3 -Gb internal
grub
 grub> root (hd0,x)
 grub> setup (hd0)
 grub> quit

Creare un raid0 (Dis+Disk+Disk..)

localhost ~ # mknod /dev/md0 b 9 0
localhost ~ # mdadm --create /dev/md0 --chunk=64 --level=raid0 --raid-devices=2 /dev/hda7 /dev/hdc1
mdadm: /dev/hda7 appears to contain a reiserfs file system
    size = 4891648K
Continue creating array? y
mdadm: array /dev/md0 started.
localhost ~ # cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md0 : active raid0 hdc1[1] hda7[0]
     303363200 blocks 64k chunks
unused devices: <none>

Creare un raid1 (Disk=Disk+Disk=Disk+..)

  • vediamo i modelli di disco che ho a disposizione: (sapendo che sono PS e SM)
[root@elwood ~]# cat /proc/ide/ide[01]/hd[bc]/model
	Maxtor 6Y160P0
	Maxtor 6L160P0

Il primo è un modello difettuoso di fabbrica (6Y***P0) Il secondo è un pò meglio

  • Faacio una partizione per disco (devono essere identiche) e togglo il file syste a linux raid autodetect (tipo fd)
# fdisk -l /dev/hd[bc]
  Device Boot      Start         End      Blocks   Id  System
/dev/hdb1               1       19929   160079661   83  Linux raid autodetect

  Device Boot      Start         End      Blocks   Id  System
/dev/hdc1               1       19929   160079661   83  Linux raid autodetect
  • formattimao il file system (ext3)
[root@elwood ~]# mkfs.ext3 -L raid1 -m0 /dev/hdb1
[root@elwood ~]# mkfs.ext3 -L raid1 -m0 /dev/hdc1
  • costruiamo e facciamo partire il raid:
[root@elwood ~]# mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/hdb1 /dev/hdc1
mdadm: /dev/hdb1 appears to contain an ext2fs file system
   size=160079660K  mtime=Mon May 29 22:32:40 2006
mdadm: /dev/hdc1 appears to contain an ext2fs file system
   size=160079660K  mtime=Thu Jan  1 01:00:00 1970
Continue creating array? (y/n) y
mdadm: array /dev/md0 started.
  • Ora vedo cosa è successo:
[root@elwood ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 hdc1[1] hdb1[0]
     160079552 blocks [2/2] [UU]
     [>....................]  resync =  0.4% (652864/160079552) finish=44.7min speed=59351K/sec
  • Con il seguente comando facciamo partire a ogni avvio la monitoria del raid che ci manderà e-mails
[root@elwood ~]# echo " nohup mdadm --monitor --mail=aledelg@gmail.com --delay=300 /dev/md0 & " >> /etc/rc.local
  • Scriviamo un paio di linee in mdadm.conf per far riavviare il raid al riavvio (non sempre necessario)
[root@elwood ~]# vi /etc/mdadm.conf
DEVICE /dev/hd[bc]1
ARRAY /dev/md0 devices=/dev/hdb1,/dev/hdc1

Rimuovere un disco

  • rimuovo la partizione /dev/hdb1 dal RAID /dev/md5
fricco ~ # mdadm --manage /dev/md5 --fail /dev/hdb1
mdadm: set /dev/hdb1 faulty in /dev/md5
fricco ~ # cat /proc/mdstat
Personalities : [linear] [raid0] [raid1]
md5 : active raid1 hdd1[1] hdb1[2](F)
     244187904 blocks [2/1] [_U]
md0 : active raid0 hdc1[1] hda7[0]
     303363200 blocks 64k chunks
unused devices: <none>
fricco ~ # mdadm --manage /dev/md5 -r /dev/hdb1
mdadm: hot removed /dev/hdb1

reset raid information of a disk

mdadm --zero-superblock /dev/<disk>

Sostituire un disco in raid1 Corrotto

  • La configurazione è la seguente:
macchina ~ # cat /proc/mdstat |grep ^md
md10 : active raid1 hdd2[1] hda2[0]
md100 : active raid1 hdd3[1] hda3[0]
md160 : active raid1 hdd5[1] hdb1[0]
md0 : active raid1 hdd1[1] hda1[0]
  • i dischi installati sono;
macchina ~ # fdisk -l 2> /dev/null|grep 'Disk /dev/hd'
Disk /dev/hda: 80.0 GB, 80000000000 bytes
Disk /dev/hdb: 163.9 GB, 163928604672 bytes
Disk /dev/hdd: 251.0 GB, 251000193024 bytes
  • il disco /dev/hdd è danneggiato:
macchina ~ # dmesg |grep hdd|tail
end_request: I/O error, dev hdd, sector 162802377
raid1: hdd5: rescheduling sector 100823408
hdd: dma_intr: status=0x51 { DriveReady SeekComplete Error }
hdd: dma_intr: error=0x40 { UncorrectableError }, LBAsect=162802376, high=9, low=11807432,  sector=162802369
end_request: I/O error, dev hdd, sector 162802369
raid1:md160: read error corrected (8 sectors at 100823536 on hdd5)
hdd: dma_intr: status=0x51 { DriveReady SeekComplete Error }
hdd: dma_intr: error=0x40 { UncorrectableError }, LBAsect=162802377, high=9, low=11807433,  sector=162802377
end_request: I/O error, dev hdd, sector 162802377
raid1:md160: read error corrected (8 sectors at 100823544 on hdd5)
  • Faccio il backup della tabella di partizioni:
sfdisk -d /dev/hdd > hdd_partition_table
  • Spengo la macchina, e monto il nuovo disco:

[... reboot ...]

  • ricario la tabella delle partizioni del vecchio disco, nel nuovo:
sfdisk /dev/hdd < hdd_partition_table
  • Añado, una por una las particiones del nuevo disco a los RAIDs
aledg ~ # mdadm /dev/md160 -a /dev/hdd5
mdadm: added /dev/hdd5
aledg ~ # mdadm /dev/md0 -a /dev/hdd1
mdadm: added /dev/hdd1
aledg ~ # mdadm /dev/md10 -a /dev/hdd2
mdadm: added /dev/hdd2
aledg ~ # mdadm /dev/md100 -a /dev/hdd3
mdadm: added /dev/hdd3
  • Miramos si esta reconstruyendo los raids, el primero que he areglado se estarà reconstruyendo, los otros , tienen que estar en estado "DELAYED" osea que se completaran uno a la vez:
aledg ~ # cat /proc/mdstat
Personalities : [raid0] [raid1] [multipath] [faulty]
md10 : active raid1 hdd2[2] hda2[0]
     10241344 blocks [2/1] [U_]
       resync=DELAYED
     bitmap: 28/157 pages [112KB], 32KB chunk
md100 : active raid1 hdd3[2] hda3[0]
     20482752 blocks [2/1] [U_]
       resync=DELAYED
     bitmap: 17/157 pages [68KB], 64KB chunk
md160 : active raid1 hdd5[2] hdb1[0]
     160079552 blocks [2/1] [U_]
     [>....................]  recovery =  0.4% (690112/160079552) finish=141.1min speed=18812K/sec
md0 : active raid1 hdd1[2] hda1[0]
     264960 blocks [2/1] [U_]
       resync=DELAYED
     bitmap: 0/33 pages [0KB], 4KB chunk
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