RAID Levels

• Linear mode: two or more disks are combined though concatenation (appended). Writing to linear RAID fills disk 0 first, then disk 1, etc.
• Disks can be of arbitrary sizes
• There is no redundancy, failure of one disk takes down the array (it may be possible to recover data from good disks)
• Performance is the same as for single disks
• No overhead (no space is lost)
• LVS provides the same functionality
• RAID-0 (stripe mode): two or more disks are combined through striping. Striping involves partitioning each drive's storage space into stripes of fixed size. These stripes are then interleaved round-robin, so that the combined space is composed alternately of stripes from each drive. Size of the stripes affects different aspects of performance.
• Disks should be of the same size
• There is no redundancy, all data is lost if one disk fails
• Read and write performance is maximized (but the gain may not be as large if the filesystem also scatters data, like ext2)
• No overhead (no space is lost)