Storage: Logical Volumes Flashcards
Device mapper
Creates virtual device and passes data from that virtual device to one or more physical devices
DM-Multipath
Provides redundancy and improved performance for block storage devices
Where do you find the config files for the multipath-tools package?
/etc/multipath.conf
mdadm
A tool used to create and manage software-based RAID arrays
/proc/mdstat File
Contains a snapshot of the kernel’s RAID/md state
How to view the RAID state?
cat /proc/mdstat
Logical Volume Manager (LVM)
Maps whole physical devices and partitions into one or more virtual containers called volume groups
What does the LVM offer?
● Dynamically create, delete, and resize volumes
● Map logical volumes across physical devices
● Create virtual snapshots of each logical volume
/dev/mapper/
contains all of the logical volumes on a system
pvscan
Scans for all physical devices being used as physical volumes
pvcreate
Initializes a drive or partition to use as a physical volume
pvdisplay
Lists attributes of physical volumes
pvs
Displays information about physical volumes
pvck
Checks the metadata of physical volumes
pvremove
Removes physical volumes
vgscan
Scans all physical devices for volume group
vgdisplay
Lists attribute of volume groups
vgs
Displays information about volume groups
vgck
Checks the metadata of volume groups
vgrename
Renames a volume group
vgextend
Adds physical volumes to volume groups
vgmerge
Merges two volume groups
vgsplit
Splits a volume group into two
vgremove
Removes volume groups
lvscan
Scans all physical devices for logical volumes
lvcreate
Creates logical volumes in a volume group
lvdisplay
Lists attributes of logical volumes
lvchange
Changes attributes of the volumes
lvs
Displays information about logical volumes
lvrename
Renames logical volumes
lvreduce
Reduces the size of logical volumes
lvextend
Extends the size of logical volumes
lvresize
Resizes logical volumes
lvremove
Removes logical volumes
