2022-01-18 12:51:14 +00:00
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---
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title: "mdadm"
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tags: [ "Documentation", "RAID" ]
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---
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2022-01-14 11:32:40 +00:00
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# RAID5
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You will need 4 disks and the `mdadm` package.
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The total size will be equal to the disks x 3, because one will be used for redundancy.
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> sudo mdadm --create --verbose /dev/*md127* --level=5 --raid-devices=*4* */dev/sdb /dev/sdc /dev/sdd /dev/sde*
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Note the variable parts:
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- The name of the device could be `/dev/md12` or whatever
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- The number of devices could be larger, but must be at least 4 for raid 5
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- We end by listing all devices in the new `md` device.
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Now look at how the raid status:
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> cat /proc/mdstat
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This will increase until the entire thing is fine.
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Check the health of your `mdadm` array:
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> sudo mdadm --detail /dev/md127
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You should see `State : clean`. If you see it is `degraded`, then a disk has broken.
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## Replacing a Disk
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> sudo mdadm --add /dev/md127 /dev/sdb1
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