Server Administration & Management

Difference between RAID and LVM

 1.  RAID is used for redundancy.  LVM is a way in which you partition the hard disk logically and it contains its own advantages.
 2.  A RAID device is a physical grouping of disk devices in order to create a logical presentation of one device to an Operating System for redundancy or performance or a combination of the two.  LVM is a logical layer that that can be anipulated in order to create and, or expand a logical presentation of a disk device to an Operating System.
 3.  RAID is a way to create a redundant or striped block device with redundancy using other physical block devices.  LVM usually sits on top of RAID blocks or even standard block devices to accomplish the same result as a partitioning, however it is much more flexible than partitions. You can create multiple volumes crossing multiple physical devices, remove physical devices without loosing data, resize the volumes, create snapshots, etc
 4.  RAID is either a software or a hardware technique to create data storage redundancy across multiple block devices based on required RAID levels.  LVM is a software tool to manage large pool of storage devices making them appear as a single manageable pool of storage resource. LVM can be used to manage a large pool of what we call Just-a-bunch-of-Disk (JBOD) presenting them as a single logical volume and thereby create various partitions for software RAID.
 5.  RAID is NOT any kind of Data backup solution. Its a solution to prevent one of the SPOFs (Single Point of Failure) i.e. DISK failure. By configuring RAID you are just providing an emergency substitute for the Primary disk. It NEVER means that you have configured DATA backup.  LVM is a disk management approach that allows us to create, extend, reduce, delete or resize the volume groups or logical volumes.

October 20, 2013 Posted by | LVM, RAID, Tips & Tricks, Unix/Linux | , , , | Leave a comment