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Hostblogger · Boot redundancyCurated

Installing GRUB on all disks of a software RAID 1

Summary

Manuel Schmitt reminds readers to make every physical drive of a Linux software RAID 1 bootable with GRUB. The article refers to the GRUB documentation for RAID 1 at the time. As examples, /dev/sda and /dev/sdb are given in device.map.

Ideas

  • A RAID 1 does not automatically protect data against a missing bootloader.
  • When a drive fails, the BIOS or GRUB numbering can change.
  • device.map maps several physical drives so that GRUB can treat each of them as hd0.
  • setup has to write the bootloader to every mirrored disk.

Insights

  • Data redundancy without a tested boot path only produces a partially highly available machine.
  • A real failure test finds boot problems that a healthy RAID never shows.

Facts

  • The GRUB shell runs setup for several drives.

Recommendations

  • Install the bootloader on all mirrored disks.
  • Test each drive on its own as the only remaining boot drive.

References

Read the original article on Hostblogger

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