Disk array system and hard disk drive expansion method thereof
Even if an arbitrary hard disk drive is added, the hard disk drive is operated in a specific operation mode suited for that hard disk drive. As triggered by attachment of a hard disk drive to a disk adapter, a processor operates the hard disk drive in a predetermined operation mode based on predetermined parameter information that has been prepared in advance. The hard disk drive stores, in advance, particular parameter information including information about the specific operation mode suited for operation. The processor reads the particular parameter information from the hard disk drive in the predetermined operation mode and operates the hard disk drive in the specific operation mode based on the particular parameter information.
1. A disk array system coupled to a host computer, comprising:
a plurality of hard disk drives;
an expander device including a memory and a plurality of ports, each port coupled to one of the plurality of hard disk drives; and
a disk controller being coupled to the expander device and controlling data transfer between the host computer and the plurality of hard disk drives via the expander device,
wherein each of the plurality of hard disk drives stores its own particular parameter information used for communication with the expander,
wherein, when the disk controller begins communication between the disk controller and a first disk drive coupled to a first port of the plurality of ports of the expander via the expander, the disk controller is configured to:
read first particular parameter information, which comprises a plurality of parameter values being suited for the communication between the expander and the first disk drive regarding an attribute of the first disk drive, from the first disk drive via the expander;
specify a first particular parameter value, which is suitable for the communication between the expander and the first disk drive based on a location to which the first disk drive is mounted from among the plurality of parameter values of the first particular parameter information; and
set the first particular parameter value on a memory of the first port of the expander and on the first disk drive so that the expander and the first disk drive can optimize a status of communication between the expander and the first disk drive based on the first particular parameter value,
wherein the first disk drive is capable of changing operating modes,
wherein before the first particular parameter value is set on the memory of the first port of the expander and on the first disk drive, the first disk drive is operated in a first operation mode in which the first disk drive communicates with the expander at a first speed rate, and
wherein after the first particular parameter value is set on the memory of the first port of the expander and on the first disk drive, the first disk drive is operated in a second operation mode in which the first disk drive communicates with expander at a second speed rate which is faster than the first speed rate.
2. A disk array system according to claim 1 ,
wherein, when the disk controller begins communication between the disk controller and a second disk drive coupled to a second port of the plurality of ports of the expander via the expander, the disk controller is configured to:
read second particular parameter information, which comprises a plurality of parameter values being suited for the communication between the expander and the second disk drive regarding an attribute of the second disk drive, from the second disk drive via the expander;
specify a second particular parameter value, which is suitable for the communication between the expander and the second disk drive based on a location to which the second disk drive is mounted, from among the plurality of parameter values of the second particular parameter information; and
set the second particular parameter value on a memory of the second port of the expander and on the second disk drive so that the expander and the second disk drive can optimize a status of communication signal between the expander and the second disk drive based on the second particular parameter value.
3. A disk array system according to claim 2 ,
wherein a length of a path for a communication between the expander and the first disk drive is different from a length of a path for a communication between the expander and the second disk drive.
4. A disk array system according to claim 2 ,
wherein the attribute of the first disk drive is different from the attribute of the second disk drive.
5. A method performed by a disk array controller in a disk array system coupled to a host computer, the disk array system having:
a plurality of hard disk drives;
an expander device including a memory and a plurality of ports, each port coupled to one of the plurality of hard disk drives; and
the disk controller being coupled to the expander device and controlling data transfer between the host computer and the plurality of hard disk drives via the expander device, wherein each of the plurality of hard disk drives stores its own particular parameter information used for communication with the expander, and wherein, when the disk controller begins communication between the disk controller and a first disk drive coupled to a first port of the plurality of ports of the expander via the expander, the method comprising the steps of:
reading first particular parameter information, which comprises a plurality of parameter values being suited for the communication between the expander and the first disk drive regarding an attribute of the first disk drive, from the first disk drive via the expander;
specifying a first particular parameter value, which is suitable for the communication between the expander and the first disk drive based on a location to which the first disk drive is mounted, from among the plurality of parameter values of the first particular parameter information; and
setting the first particular parameter value on a memory of the first port of the expander and on the first disk drive so that the expander and the first disk drive can optimize a status of communication between the expander and the first disk drive based on the first particular parameter value,
wherein the first disk drive is capable of changing operating modes,
wherein before the first particular parameter value is set on the memory of the first port of the expander and on the first disk drive, the first disk drive is operated in a first operation mode in which the first disk drive communicates with the expander at a first speed rate, and
wherein after the first particular parameter value is set on the memory of the first port of the expander and on the first disk drive, the first disk drive is operated in a second operation mode in which the first disk drive communicates with the expander at a second speed rate which is faster than the first speed rate.
6. A method according to claim 5 , wherein, when the disk controller begins communication between the disk controller and a second disk drive coupled to a second port of the plurality of ports of the expander via the expander, the method further comprising the steps of:
reading second particular parameter information, which comprises a plurality of parameter values being suited for the communication between the expander and the second disk drive regarding an attribute of the second disk drive, from the second disk drive via the expander;
specifying a second particular parameter value, which is suitable for the communication between the expander and the second disk drive based on a location to which the second disk drive is mounted, from among the plurality of parameter values of the second particular parameter information; and
setting the second particular parameter value on a memory of the second port of the expander and on the second disk drive so that the expander and the second disk drive can optimize a status of communication signal between the expander and the second disk drive based on the second particular parameter value.
7. A method according to claim 6 ,
wherein a length of a path for a communication between the expander and the first disk drive is different from a length of a path for a communication between the expander and the second disk drive.
8. A method according to claim 6 ,
wherein the attribute of the first disk drive is different from the attribute of the second disk drive.