Which command is used to make an exact copy, at a single point in time, of a logical volume while still allowing the original logical volume to be updated?
Which command is used to make an exact copy, at a single point in time, of a logical volume while still allowing the original logical volume to be updated?
The command used to make an exact copy, at a single point in time, of a logical volume while still allowing the original logical volume to be updated is 'lvcreate'. The 'lvcreate' command with the '-s' option creates a snapshot of the logical volume. This snapshot is a virtual copy, which means it can be used to access the state of the logical volume at the time the snapshot was taken while the original logical volume can continue to be updated.
LVM Snapshots Snapshots One of the nicest features of LVM is the possibility of taking snapshots of volumes. A snapshot is a virtual copy of the volume to enable easy backups. LVM snapshots use a strategy called "copy on write". This means that the snapshot logical volume only saves data blocks from the original logical volume that are changed in the original logical volume. To do so the logical volume manager first reads the (unchanged) data block on the original and than writes the data block to the snapshot. On filesystems with many changes (e.g. databases) this can lead to performance issues. The -s option in the lvcreate command specifies that the newly created logical volume is a snapshot. # lvcreate -L 50M -s -n snapshot0 /dev/volume01/lvol0
B - 100%
I'm a bit confused about this, because to do a full clone of a LV you can use: lvcreate --snapshot --name <the-name-of-the-snapshot> --size <the size> /dev/<volume-group>/<logical-volume> This will create a Snapshot but to clone it on another LV would need the "dd" command additionally.... So to create a snapshot (if this is meant by "Clone") you might use lvcreate. Anyone here with knowhow in GV/ LV/ PV?
there is no needed for `dd`. LVM, Logical Volume Management, was instructed with `--snapshot` to also deal with content on the PE, Physical Extent.
B is correct
I vote for B. There are no lvcclone, lvm2, lvsnap, lvsnapshot commands.
lvcreate -L size -s -n snapname origlv