Re: Raid 10 Issue - Booting in case raid failed

[Stefan Lamby <webmaster@peter-speer.de>]

Hi list.

If everything will work out OK, I will end up with an raid 10 array with 4
devices.

My partition design and layout structure will be found at the end, if needed.

There are a few questions left for me in case I have to boot with a failed disk:

1) As you might have seen from the partition design, only partition sda1 has the
boot flag set. As far as I guess, the ubuntu installer was using grub-install
only for sda. I am kind of afraid what will happen, in case sda will fail in the
future. Will it be a good idea to grub-install to all the other devices also?
2) What about the boot flag, if I need to grub-install the other devices also?
Should it be O or 1? Do I have to leave it set to false and in case things go
wrong boot from a live cd and set it to on to boot from another device?

What do you recommend?

Thanks
Stefan




Here is my layout - please do not care

root@kvm15:~# fdisk -l /dev/sda

Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
255 Köpfe, 63 Sektoren/Spur, 243201 Zylinder, zusammen 3907029168 Sektoren
Einheiten = Sektoren von 1 × 512 = 512 Bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Festplattenidentifikation: 0x00071c2b

   Gerät  boot.     Anfang        Ende     Blöcke   Id  System
/dev/sda1   *    98435072  3907028991  1904296960   fd  Linux raid autodetect

Here as an example for all other disks

Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes
255 Köpfe, 63 Sektoren/Spur, 243201 Zylinder, zusammen 3907029168 Sektoren
Einheiten = Sektoren von 1 × 512 = 512 Bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Festplattenidentifikation: 0x0008624b

   Gerät  boot.     Anfang        Ende     Blöcke   Id  System
/dev/sdb1        98435072  3907028991  1904296960   fd  Linux raid autodetect

PCI [ahci] 00:1f.2 SATA controller: Intel Corporation 82801JI (ICH10 Family)
SATA AHCI Controller
├scsi 2:0:0:0 ATA      WDC WD20PURX-64P {WD-WCC4M1LPT1AE}
│└sda 1.82t [8:0] Partitioned (dos)
│ └sda1 1.77t [8:1] MD raid10,near2 (0/2) (w/ sdb1) in_sync 'kvm15:0'
{75079a2f-acb8-c475-85f8-ca430ad85c4c}
│  └md0 1.77t [9:0] MD v1.2 raid10,near2 (2) clean, 512k Chunk
{75079a2f:acb8c475:85f8ca43:0ad85c4c}
│   │               PV LVM2_member 1.01t used, 780.45g free
{2hsby0-0FOT-PPbC-il1r-ux9J-lUd2-nPHj7T}
│   └VG vg_raid10 5.32t (w/ md10) 3.30t free
{HbjouC-RgUe-YYNB-z2ns-4kzK-RwJH-RHWSWq}
│    ├dm-0 479.39g [252:0] LV home ext4 {2d67d9cc-0378-4669-9d72-7b7c7071dea8}
│    │└Mounted as /dev/mapper/vg_raid10-home @ /home
│    ├dm-1 93.13g [252:1] LV root ext4 {c14e4524-e95c-45c2-bfa0-75d529ed48fe}
│    │└Mounted as /dev/mapper/vg_raid10-root @ /
│    ├dm-4 23.28g [252:4] LV swap swap {9e1a582f-1c88-44a2-be90-aafcb96805c7}
│    ├dm-3 46.56g [252:3] LV tmp ext4 {ac67d0d9-049c-4cf2-9a0e-591cdb6a3559}
│    │└Mounted as /dev/mapper/vg_raid10-tmp @ /tmp
│    └dm-2 393.13g [252:2] LV var ext4 {ff71c558-c1f8-4410-8e2a-dc9c77c27a03}
│     └Mounted as /dev/mapper/vg_raid10-var @ /var
├scsi 3:0:0:0 ATA      WDC WD20PURX-64P {WD-WCC4M5LAR62D}
│└sdb 1.82t [8:16] Partitioned (dos)
│ └sdb1 1.77t [8:17] MD raid10,near2 (1/2) (w/ sda1) in_sync 'kvm15:0'
{75079a2f-acb8-c475-85f8-ca430ad85c4c}
│  └md0 1.77t [9:0] MD v1.2 raid10,near2 (2) clean, 512k Chunk
{75079a2f:acb8c475:85f8ca43:0ad85c4c}
│                   PV LVM2_member 1.01t used, 780.45g free
{2hsby0-0FOT-PPbC-il1r-ux9J-lUd2-nPHj7T}
├scsi 4:0:0:0 ATA      WDC WD20PURX-64P {WD-WCC4M7YA1ANR}
│└sdc 1.82t [8:32] Partitioned (dos)
│ └sdc1 1.77t [8:33] MD raid10,near2 (1/4) (w/ sdd1) in_sync 'kvm15:10'
{c4540426-9c66-8fe2-4795-13f242d233b4}
│  └md10 3.55t [9:10] MD v1.2 raid10,near2 (4) active DEGRADEDx2, 512k Chunk
{c4540426:9c668fe2:479513f2:42d233b4}
│   │                 PV LVM2_member 1.01t used, 2.54t free
{wYV8fH-uOp2-E88P-EIp5-6U33-chYg-S94vvy}
│   └VG vg_raid10 5.32t (w/ md0) 3.30t free
{HbjouC-RgUe-YYNB-z2ns-4kzK-RwJH-RHWSWq}
└scsi 5:0:0:0 ATA      WDC WD20PURX-64P {WD-WCC4M5AFRYVP}
 └sdd 1.82t [8:48] Partitioned (dos)
  └sdd1 1.77t [8:49] MD raid10,near2 (3/4) (w/ sdc1) in_sync 'kvm15:10'
{c4540426-9c66-8fe2-4795-13f242d233b4}
   └md10 3.55t [9:10] MD v1.2 raid10,near2 (4) active DEGRADEDx2, 512k Chunk
{c4540426:9c668fe2:479513f2:42d233b4}
                      PV LVM2_member 1.01t used, 2.54t free
{wYV8fH-uOp2-E88P-EIp5-6U33-chYg-S94vvy}
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html