Concept :: More on Linux Multipathing

This is how the EVMS and LVM2 interact with the Device mapper . EVMS(Enterprise. Vol Mgmt System) and the LVM2( an extension to Logical Vol Mgmt System (LVM) for 2.4) are user interfaces to interact with the kernel on logical device mgmt.

Basic SCSI terminologies around multipathing:

Physicalpath -> Unique combination of a SCSIinitiator and a SCSItarget,

Device -> SCSI Logicalunit ,

Path -> Logical Connection along a physical path to a prticular device.

Also read - > multipathing user-space tools like multipath , dmsetup , dmraid , udev , hotplug.

Concepts :: gGlossary pick

Appliance - A network product designed to perform a specialized task with minimal user administration . In storage virtualization , an appliance is an embedded virtualization engine attached to a SAN.

Block level addressing - An algoithm for identifying blocks of data stored on disk / tape by number. Also known as Logical Block Addressing (LBA). Block address numbers are converted to physical locations on storage such as cylinder , head , sector for disk media.

CDB - Known as SCSI Command Descriptor Block. Used to transfer commands, status, data between an Initiator and Target through SCSI.