SAN School Quiz 2 Answer # 8 |
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08 Jan 2004 | SearchStorage.com |
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Question #8
The amount of work that an HBA can push out to a storage disk array is determined by:
a.Time out settings.
b.Persistent binding values.
c.Fibre channel switches.
d.LUN throttle values.
Were you correct? The correct answer is
d. LUN throttle values.
Learn more:
A LUN The logical unit described here is different than the logical unit of IBM's Systems Network Architecture (SNA).
A logical unit number (LUN) is a unique identifier used on a SCSI bus that enables it to differentiate between up to eight separate devices (each of which is a logical unit). Each LUN is a unique number that identifies a specific logical unit, which may be an end user, a file, or an application program.
A SCSI (Small System Computer Interface) is a parallel interface, that can have up to eight devices all attached through a single cable; the cable and the host (computer) adapter make up the SCSI bus. The bus allows the interchange of information between devices independently of the host. In the SCSI program, each device is assigned a unique number, which is either a number between 0 and 7 for an 8-bit (narrow) bus, or between 8 and 16 for a 16-bit (wide) bus. The devices that request input/output (I/O) operations are initiators and the devices that perform these operations are targets. Each target has the capacity to connect up to eight additional devices through its own controller; these devices are the logical units, each of which is assigned a unique number for identification to the SCSI controller for command processing.
Related articles:
Taming HBAs
Taming HBAs, Part 2
Taming HBAs, Part 3
Sorting out the features
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