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  mdadm:  	PREPARE DRIVES: 		fdisk /dev/sdb 		n - new 		p - primary partition 		w - write 		(repeat for each drive) 		 	LARGER THAN 2TB PARTITIONS: 		parted /dev/sdb 		mk..."

2016-02-29T21:23:35Z

Created page with "<pre> mdadm: PREPARE DRIVES: fdisk /dev/sdb n - new p - primary partition w - write (repeat for each drive) LARGER THAN 2TB PARTITIONS: parted /dev/sdb mk..."

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<pre>

mdadm:

PREPARE DRIVES:
fdisk /dev/sdb
n - new
p - primary partition
w - write
(repeat for each drive)

LARGER THAN 2TB PARTITIONS:
parted /dev/sdb
mklabel gpt - create GPT partition table instead of msdos
unit tb - make default units in TB
mkpart primary 0 3 - create the partition on whole disk (0 3 is 'start' and 'end' in TB)
print - print partition info

CREATE RAID:
mdadm --create --verbose /dev/md0 --level=0 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1 - creates raid-0 on /dev/md0 from the 3 devices
mdadm -C -v /dev/md0 -l 0 -n 3 /dev/sdb1 /dev/sdc1 /dev/sdd1 - short version

PARAMETERS:
--name <name> - give the array a name.
--force - force the operation. can be used to create a raid with a single drive to recover data.

SAVE CONFIGURATION:
mdadm --detail --scan >> /etc/mdadm/mdadm.conf (ubuntu)
mdadm --detail --scan >> /etc/mdadm.conf (other distributions)
update-initramfs -u - saves md config to init. (this allows the correct dev name to be used instead of md127)

CHECKING:
cat /proc/mdstat
mdadm --detail /dev/md0 - show details of raid. shows progress of data being rebuilt
mdadm --monitor --mail=admin@example.com --delay=1800 /dev/md0 - email status (delay in seconds)
mdadm --examine /dev/sdb1 - examine details of drive

MANAGING:
mdadm --stop /dev/md0
mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 - start raid with these devices
mdadm --assemble --scan - start all stopped raid

REMOVE RAID:
umount /dev/md0
mdadm --stop /dev/md0
mdadm --zero-superblock /dev/sdb1
mdadm --zero-superblock /dev/sdc1
(remember to remove line from fstab)

REMOVE DRIVE:
umount /dev/md0
mdadm /dev/md0 --fail /dev/sdc1
mdadm /dev/md0 --remove /dev/sdc1

REBUILD:
mdadm /dev/md0 --add /dev/sdd1 - add drive to array. drive must be partitioned just like the original. Data will then be rebuilt.

mkfs:
mkfs -t ext4 -L LABEL /dev/md0 - creates filesystem on raid device

</pre>

Mdadm - Revision history

Beard: Created page with "
mdadm: PREPARE DRIVES: fdisk /dev/sdb n - new p - primary partition w - write (repeat for each drive) LARGER THAN 2TB PARTITIONS: parted /dev/sdb mk..."