4. Storage

LVM Snapshots of Mirrors

The LVM snapshot feature provides the ability to create backup images of a logical volume at a particular instant without causing a service interruption. When a change is made to the original device (the origin) after a snapshot is taken, the snapshot feature makes a copy of the changed data area as it was prior to the change so that it can reconstruct the state of the device. In Red Hat Enterprise Linux 6.1 the ability to take a snapshot of a mirrored logical volume is a fully supported feature.

LVM Stripe of Mirrors

It is now possible to combine RAID0 (striping) and RAID1 (mirroring) in a single logical volume in LVM. Creating a logical volume while simultaneously specifying the number of mirrors ('--mirrors X') and the number of stripes ('--stripes Y') results in a mirror devices whose constituent devices are striped.