Storage system

1. A storage system comprising a storage controller having multiple types of physical resources used for processing I/O requests from a host, and a media resource for storing data;

the multiple types of physical resources including, at least, a processor resource, a memory resource, and a port resource connected to the host;

the storage system being configured to be able to create one or more virtual storage subsystems to which virtual resources having logically divided a processing capacity of the physical resources are allocated,

wherein when a virtual storage subsystem of the one or more virtual storage subsystems creates a virtual volume for receiving I/O requests from the host within the virtual storage subsystem, the virtual storage subsystem allocates a virtual resource of the virtual resources to the virtual volume based on a target performance and a target resource utilization rate of the virtual volume,

wherein when the virtual storage subsystem receives an I/O request to the virtual volume from the host, the virtual storage subsystem performs processing related to the I/O request using the virtual resource having been allocated, and

wherein after allocating the virtual resource to the virtual volume, the storage system changes the virtual resource having been allocated to the virtual volume based on the target performance and the target resource utilization rate, and concurrently raises the target resource utilization rate in a stepwise manner,

wherein the storage system allocates the virtual resource to the virtual volume based on a ratio of volume size of the virtual volume and a total value of size of all volumes in the virtual storage subsystem, and

wherein after allocating the virtual resource to the virtual volume, prior to raising the target resource utilization rate in a stepwise manner, the storage system is configured to:

A) calculate an average value of utilization rates of the virtual resources allocated to respective virtual volumes within the virtual storage subsystem;

B) calculate a virtual resource amount of the virtual resource required to achieve the target performance, based on a performance of the respective virtual volumes at a current point of time, a predetermined target performance, and a resource amount of the virtual resource being used at the current point of time; and

C) determine a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following:

(the virtual resource amount required to achieve the target performance)÷(the average value of utilization rates of the virtual resources)÷(a maximum processing capacity of the physical resources).

2. The storage system according to claim 1 , wherein

when raising the target resource utilization rate in a stepwise manner, the storage system is configured to:

D) calculate the target resource utilization rate by adding a predetermined amount to the average value of utilization rates of the virtual resources; and

E) determine a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following:

the virtual resource amount required to achieve the target performance÷the target resource utilization rate÷the maximum processing capacity of the physical resource.

3. A storage system comprising a storage controller having multiple types of physical resources used for processing I/O requests from a host, and a media resource for storing data;

the multiple types of physical resources including, at least, a processor resource, a memory resource, and a port resource connected to the host;

the storage system being configured to be able to create one or more virtual storage subsystems to which virtual resources having logically divided a processing capacity of the physical resources are allocated,

wherein when a virtual storage subsystem of the one or more virtual storage subsystems creates a virtual volume for receiving I/O requests from the host within the virtual storage subsystem, the virtual storage subsystem allocates a virtual resource of the virtual resources to the virtual volume based on a target performance and a target resource utilization rate of the virtual volume,

wherein when the virtual storage subsystem receives an I/O request to the virtual volume from the host, the virtual storage subsystem performs processing related to the I/O request using the virtual resource having been allocated,

wherein after allocating the virtual resource to the virtual volume, the storage system changes the virtual resource having been allocated to the virtual volume based on the target performance and the target resource utilization rate, and concurrently raises the target resource utilization rate in a stepwise manner,

wherein the storage system allocates the virtual resource to the virtual volume based on a ratio of volume size of the virtual volume and a total value of size of all volumes in the virtual storage subsystem,

wherein after allocating the virtual resource to the virtual volume, prior to raising the target resource utilization rate in a stepwise manner, the storage system is configured to:

A) calculate an average value of utilization rates of the virtual resources allocated to the respective virtual volumes within the virtual storage subsystem; and

B) determine a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following:

an amount of resource of the virtual resource being used at the current point of time÷the average value of utilization rates of the virtual resources÷the maximum processing capacity of the physical resources.

4. The storage system according to claim 3 , wherein

when raising the target resource utilization rate in a stepwise manner, the storage system is configured to:

C) calculate the target resource utilization rate by adding a predetermined amount to an average value of the virtual resource utilization rates; and

D) determine a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following:

the amount resource of the virtual resource being used at the current point of time÷the average value of utilization rates of the virtual resources÷the maximum processing capacity of the physical resource.

5. A method for controlling a storage system comprising a storage controller having multiple types of physical resources used for processing I/O requests from a host, and a media resource for storing data;

the multiple types of physical resources including, at least, a processor resource, a memory resource, and a port resource connected to the host; and

the storage system being configured to be able to create one or more virtual storage subsystems to which virtual resources having logically divided a processing capacity of the physical resources are allocated,

the method comprising the steps of:

upon creating a virtual volume for receiving I/O requests from the host within a virtual storage subsystem of the one or more virtual storage subsystems, allocating a virtual resource of the virtual resources to the virtual volume based on a target performance and a target resource utilization rate of the virtual volume, and when an I/O request to the virtual volume is received from the host, performing processing related to the I/O request using the virtual resource having been allocated;

after allocating the virtual resource to the virtual volume, changing the virtual resource having been allocated to the virtual volume based on the target performance and the target resource utilization rate, and concurrently raising the target resource utilization rate in a stepwise manner;

allocating the virtual resource to the virtual volume based on a ratio of volume size of the virtual volume and a total value of size of all volumes of the virtual storage subsystem; and

after allocating the virtual resource to the virtual volume, prior to raising the target resource utilization rate of the virtual resource allocated to the virtual volume in a stepwise manner, the method further comprising the steps of:

A) calculating an average value of utilization rates of the virtual resources allocated to respective virtual volumes within the virtual storage subsystem;

B) calculating a virtual resource amount of the virtual resource required to achieve the target performance, based on a performance of the respective virtual volumes at a current point of time and a determined target performance, and a resource amount of the virtual resource being used at the current point of time; and

C) determining a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following:

(the virtual resource amount required to achieve the target performance)÷(the average value of utilization rates of the virtual resources)÷(a maximum processing capacity of the physical resources).

6. The method for controlling a storage system according to claim 5 , wherein

when raising the target resource utilization rate in a stepwise manner, the method further comprises the steps of:

D) calculating the target resource utilization rate by adding a predetermined amount to an average value of the virtual resource utilization rates; and

E) determining a ratio of resource amount to be allocated to the virtual volume from the physical resources by calculating the following: (the virtual resource amount required to achieve the target performance)÷(the average value of utilization rates of the virtual resources)÷(a maximum processing capacity of the physical resources).