What is RAID?
RAID is a method by which information is spread across several disks, using techniques to achieve redundancy, lower latency and/or higher bandwidth for reading and/or writing to disk, and maximize recoverability from hard-disk crashes.
Is it true that using linear RAID increases the level of redundancy?
No, in fact it decreases reliability -- if any one member drive fails, the entire array cannot be used.
How would you automate RAID activation after reboot using
Run mdadm --assemble -s in one of the startup files.
What is the objective of using Logical Volume Management (LVM)?
It enables you to concatenate several physical volumes (hard disk, etc) to a so-called volume group, forming a storage pool.
What is a Logical Volume (LV)?
A Logical Volume is created based on a number of Physical Extents (PE) taken from a Volume Group (VG) on top of which a filesystem can be built.