Storage system and controlling method therefor
With a storage system including a drive and a controller, which are connected to each other via cables, and with a method for controlling the storage system, an emergency power supply voltage for a power failure at the drive is multiplexed at the controller with a first signal to be sent to the drive, and the resultant emergency power supply voltage is sent via the cable to the drive. When a power failure occurs at the drive, the drive is powered with the emergency power supply voltage sent from the controller, and specified power failure information is multiplexed at the drive with a second signal to be sent to the controller, and the resultant power failure information is then sent via the cable to the controller; and specified processing is executed at the controller in response to the power failure information sent from the drive via the cable. Accordingly, it is possible to realize a storage system and the controlling method therefor that are adequate for practical applications and can sufficiently cope with drive power failures without the need for complication and upsizing of the entire system configuration.
1. A storage system comprising:
a drive for driving a storage device to store data; and
a controller for controlling input and output of the data between a host system and the drive,
the drive and the controller being connected to each other via a cable;
wherein the controller includes:
a first power supply unit for outputting an emergency power supply voltage when a power failure occurs at the drive;
a first multiplexing unit for multiplexing the emergency power supply voltage output from the first power supply unit, with a first signal to be sent to the drive and sending the resultant emergency power supply voltage via the cable to the drive; and
a failure processing unit for executing specified processing in response to power failure information sent from the drive via the cable; and
wherein when a power failure occurs at the drive, the drive is powered with the emergency power supply voltage sent from the controller; the drive including:
a failure detecting unit for outputting the power failure information; and
a second multiplexing unit for multiplexing the power failure information output from the failure detecting unit with a second signal to be sent to the controller and sending the resultant power failure information via the cable to the controller.
2. The storage system according to claim 1 , wherein the cable includes:
a first transmission line for sending the first signal from the controller to the drive; and
a second transmission line for sending the second signal from the drive to the controller; and
wherein the first multiplexing unit sends the first signal and the emergency power supply voltage, which are multiplexed, via the first transmission line to the drive; and
the second multiplexing unit sends the second signal and the power failure information, which are multiplexed, via the second transmission line to the controller.
3. The storage system according to claim 1 , wherein the first multiplexing unit includes a first filter for separating and extracting the second signal from a multiplexed signal produced by multiplexing the second signal and the power failure information.
4. The storage system according to claim 1 , wherein the second multiplexing unit includes a second filter for separating and extracting the first signal from a multiplexed signal produced by multiplexing the first signal and the emergency power supply voltage.
5. The storage system according to claim 1 , wherein the failure processing unit includes a third filter for separating and extracting the power failure information from a multiplexed signal produced by multiplexing the second signal and the power failure information.
6. The storage system according to claim 1 , wherein the failure detecting unit includes a fourth filter for separating and extracting the emergency power supply voltage from a multiplexed signal produced by multiplexing the first signal and the emergency power supply voltage.
7. The storage system according to claim 1 , wherein the controller sends a clock signal of a specified frequency, which is different from the frequencies of the first signal and the second signal, via the cable to the drive, and
the drive sends the power failure information via the cable to the controller in synchronization with the clock signal.
8. The storage system according to claim 7 , wherein the drive includes a register for storing a number of kinds of failure information, including the power failure information, at respective different addresses;
the controller sends the address of the register where the failure information to be acquired is stored, via the cable to the drive in synchronization with the clock signal; and
the drive reads, from the register, the failure information stored at the corresponding address of the register and sends the read failure information via the cable to the controller in synchronization with the clock signal.
9. The storage system according to claim 1 , wherein the first signal is a signal that contains a data read request and is sent from the controller to the drive, and
the second signal is a signal that contains the data read from the storage device in response to the read request and is sent from the drive to the controller.
10. A method for controlling a storage system including a drive for driving a storage device to store data, and a controller for controlling input and output of the data between a host system and the drive, the drive and the controller being connected to each other via a cable;
wherein the storage system controlling method comprises:
a first step performed at the controller of multiplexing an emergency power supply voltage for a power failure at the drive, with a first signal to be sent to the drive and sending the resultant emergency power supply voltage via the cable to the drive;
a second step performed at the drive when a power failure occurs at the drive, of powering the drive with the emergency power supply voltage sent from the controller, multiplexing specified power failure information with a second signal to be sent to the controller, and sending the resultant power failure information via the cable to the controller; and
a third step performed at the controller of executing specified processing in response to the power failure information sent from the drive via the cable.
11. The storage system controlling method according to claim 10 , wherein the cable includes:
a first transmission line for sending the first signal from the controller to the drive; and
a second transmission line for sending the second signal from the drive to the controller; and
wherein in the first step the first signal and the emergency power supply voltage, which are multiplexed, are sent via the first transmission line to the drive; and
in the second step the second signal and the power failure information, which are multiplexed, are sent via the second transmission line to the controller.
12. The storage system controlling method according to claim 10 , wherein in the second step the controller sends a clock signal of a specified frequency, which is different from frequencies of the first signal and the second signal, via the cable to the drive, and
the drive sends the power failure information via the cable to the controller in synchronization with the clock signal.
13. The storage system controlling method according to claim 12 , wherein the drive includes a register for storing a number of kinds of failure information, including the power failure information, at respective different addresses; and
in the second step the controller sends the address of the register where the failure information to be acquired is stored, via the cable to the drive in synchronization with the clock signal; and
the drive reads, from the register, the failure information stored at the corresponding register address and sends the read failure information via the cable to the controller in synchronization with the clock signal.
14. The storage system controlling method according to claim 10 , wherein the first signal is a signal that contains a data read request and is sent from the controller to the drive, and
the second signal is a signal that contains the data read from the storage device in response to the read request and is sent from the drive to the controller.