Copied from https://gist.github.com/plepe
mdadm
md: multiple devices
command description
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cat /proc/mdstat |
show status of all raids
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mdadm --detail /dev/md0 |
detailed status of raid md0
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mdadm --create /dev/md0 -n2 -l1 /dev/sda1 /dev/sdb1 |
new raid /dev/md0 with 2 disks, raid level 1 on /dev/sda1 and /dev/sda2
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mdadm --fail /dev/md0 /dev/sda1 |
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mdadm --remove /dev/md0 /dev/sda1 |
remove /dev/sda1 from /dev/md0
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mdadm --add /dev/md0 /dev/sda1 |
add /dev/sda1 to /dev/md0
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mdadm --grow /dev/md0 -n3 |
use 3 disks in raid /dev/md0 (e.g. add an additional disk, so a damaged drive can be removed later-on)
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mdadm --assemble /dev/md0 |
Assemble /dev/md0 (e.g. when running live system)
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mdadm --detail --scan >> /etc/mdadm/mdadm.conf |
Update list of arrays in /etc/mdadm/mdadm.conf ; you should remove old list by hand first!
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mdadm --examine /dev/sda1 |
What is this disk / partition?
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sysctl -w dev.raid.speed_limit_min=10000 |
Set minimum raid rebuilding speed to 10000 kiB/s (default 1000)
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sfdisk -d /dev/sdX | sfdisk /dev/sdY |
Copy partition table from sdX to sdY (MBR only)
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sgdisk /dev/sdX -R /dev/sdY ; sgdisk -G /dev/sdY |
Copy partition table from sdX to sdY (GPT)
To boot a machine even with a degraded array, modify /etc/initramfs-tools/conf.d/mdadm and run update-initramfs -c -kall (Use with caution!)
LVM
pv: physical device (e.g. /dev/md0 or /dev/sda1)
vg: volume group (consists of 1 or more pvs, contains lvs); has a name (e.g. lvm)
lv: logical volume (has a name which defines its path, e.g. /dev/lvm/root which equals dev/mapper/lvm-root)
command description
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pvcreate /dev/md0 |
initializes /dev/md0 as phys device for a volume group
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vgcreate lvm /dev/md0 |
create volume group lvm with phys device /dev/md0
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lvcreate -L30G -nroot lvm ; mkfs.ext4 /dev/lvm/root |
create logical volume root, sized 30G in volume group lvm; format with ext4
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lvextend -L60G -nroot lvm ; resize2fs /dev/lvm/root |
extend /dev/lvm/root to 60G; also resize file system to new size
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pvs, vgs, lvs |
show short info about pv, vg and lv
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pvdisplay, vgdisplay, lvdisplay |
show long info
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pvscan /dev/md0 |
scan disks for physical volumes (e.g. when running live system)
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vgextend lvm /dev/md1 |
add phys device /dev/md1 to volume group lvm (need pvcreate first!)
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pvmove /dev/md0 ; vgreduce lvm /dev/md0 |
move all logical volumes from /dev/md0 and remove phys device from volume group
Other
create bios grub partition
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parted mklabel gpt unit s mkpart bios 64s 2047s set 1 bios_grub on mkpart NAME 2048s [end] |
