I had noticed that many new admins and end user get confused with RAID concept. Many think that RAID 0 offers backup protection.
A few points:
a) Redundant array of independent disks (RAID) refers to a data storage scheme using multiple hard drives to share or replicate data among the drives.
b) No matter which RAID array you use backup regularly.
c) For performance always use hardware based RAID controller. If you are tight on budget go for software based RAID. For any production environment I recommend hardware based RAID controller.
c) To make your decision final regarding RAID consider following points:
Your requirements
- Fault tolerant
- Speed vs performance vs overhead
- Your application and required bandwidth
- Final Cost
(click to enlarge image)
To make your life easy there is a tutorial available online. This tutorial offers:
=> Characteristics of each RAID array
=> Advantages and disadvantages of each RAID array
=> Required number of hard disk for each array
=> Suggested application of each RAID array
See RAID tutorial [acnc.com]
how to format a hard disk which was deleted completely?
Use mkfs.ext3 to format hardisk.
The tutorial does not describe RAID10 fully, in particular Linux RAID10 is not described. Linux RAID10 only requires 2 drives, and it can perform like RAID0 for reading (in the far layout) and IMHO it is not expensive. It scales well, and can employ even and odd numbers of drives