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LVM

LVM functions by layering abstractions on top of physical storage devices. The basic layers that LVM uses, starting with the most primitive, are.

  • Physical Volumes:
    • LVM utility prefixpv...
    • Description: Physical block devices or other disk-like devices (for example, other devices created by device mapper, like RAID arrays) are used by LVM as the raw building material for higher levels of abstraction. Physical volumes are regular storage devices. LVM writes a header to the device to allocate it for management.
    Volume Groups:
      LVM utility prefixvg... Description: LVM combines physical volumes into storage pools known as volume groups. Volume groups abstract the characteristics of the underlying devices and function as a unified logical device with combined storage capacity of the component physical volumes. Logical Volumes:
        LVM utility prefixlv... (generic LVM utilities might begin with lvm...) Description: A volume group can be sliced up into any number of logical volumes. Logical volumes are functionally equivalent to partitions on a physical disk, but with much more flexibility. Logical volumes are the primary component that users and applications will interact with.

        Create a volume group

        pvcreate /dev/sda1 /dev/sdb1
        vgcreate vol_group_name /dev/sda1 /dev/sdb1
        lvcreate -l 95%FREE -n drive_name vol_group_name

        View info on group

        pvscan
        pvdisplay
        vgdisplay
        lvdisplay

        Mount LVM (Perfect for rescue env)

        pvscan                 
        vgscan                 
        vgchange -ay           
        lvscan    
        mount /dev/VolGroup00/LogVol00 /mnt

        Full Doc: