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# mdadm --manage --fail /dev/md1 /dev/sdb2mdadm: set /dev/sdb2 faulty in /dev/md1# mdadm --manage --remove /dev/md1 /dev/sdb2mdadm: hot removed /dev/sdb2 from /dev/md1# mdadm --zero-superblock /dev/sdb2mdadm: Unrecognised md component device - /dev/sdb2[probably failed normally works; the example above was because sdb was badhad failed]# echo "1" > /sys/block/sdb/device/delete
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GRUB2 can be configured to include md support so can assemble the /boot md before loading initrd (or the kernel directly) but Blue Light does not do this.
Start all md devices
Some linux system integrated an mdadm tool called mdadm-startall. You can install it if not already done.
It doesn't require any argument and will assemble all the md devices found.
...
accepts what the distro delivers.
Routine maintenance
checkarray
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/usr/share/mdadm/mkconf > /etc/mdadm/mdadm.conf
mdadm syntax table
In case mdadm --help and the mdam man page are not what is needed.
The man page says the general syntax is
mdadm [mode] [options] <component-devices>
But that does not agree with mdadm --help output which lists ... mdadm mode device options... mdadm mode [option ...] devices
... and notes that the --manage mode can be omitted.
BusyBox mdam commands are more consistent than the full commands; options always come before devices.
Mode | device before options | Options | Notes |
|---|---|---|---|
| --assemble | Y | bitmap, uuid, super-minor, name, config, scan, run, force, update, no-degraded | |
| --build | Y | ||
| --create | Y | ||
| --grow | N | ||
| --incremental | No options | ||
| --misc | N | ||
| --manage | Y | add, remove, fail, set-faulty, run, stop, readonly, readwrite | --manage may be omitted |
| --monitor | No device |
Troubleshooting
initrd fails to assemble md devices
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