On-demand cache memory for storage subsystems

1. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a processor to perform operations for managing adjustments to a cache size of a cache memory in view of supporting an optimal performance of a storage subsystem employing the cache memory, the operations comprising:

determining an optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem; and

reporting any size adjustment to the cache size of the cache memory based on the determination of the optimal cache size of the cache memory to thereby facilitate a management of a client expense account associated with the cache memory.

2. The signal bearing medium of claim 1 , wherein determining the optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem includes:

measuring a performance of the storage subsystem for each prospective cache size of the cache memory.

3. The signal bearing medium of claim 2 , wherein determining the optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem further includes:

determining the optimal cache size of the cache memory based on a comparison of the measured performances of the storage subsystem for the prospective cache sizes of the cache memory.

4. The signal bearing medium of claim 2 , wherein measuring the performance of the storage subsystem for each prospective cache size of the cache memory includes:

measuring at least one of a I/O operation rate, a data throughput rate, and a cache hit ratio for each prospective cache size of the cache memory.

5. The signal bearing medium of claim 4 , wherein determining the optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem further includes:

comparing at least one of I/O operation rates, data throughput rates, and cache hit ratios for the prospective cache sizes of the cache memory.

6. The signal bearing medium of claim 2 , wherein measuring the performance of the storage subsystem for each prospective cache size of the cache memory further includes:

generating a composite performance rate for each prospective cache size of the cache memory, wherein each composite performance rate is a function of at least one of the I/O operation rate measurement, the data throughput rate measurement, and the cache hit ratio measurement of the corresponding prospective cache size of the cache memory.

7. The signal bearing medium of claim 6 , wherein determining the optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem further includes:

comparing composite performance rates for the prospective cache sizes of the cache memory.

8. The signal bearing medium of claim 2 , wherein determining the optimal cache size of the cache memory for supporting the optimal performance of the storage subsystem includes:

setting the cache size of the cache memory to the determined optimal cache size of the cache memory in response to the measured performance of the determined optimal cache size complying with a performance parameter associated with the client expense account.

9. The signal bearing medium of claim 1 , wherein reporting any size adjustment to the cache size of the cache memory based on the determination of the optimal cache size of the cache memory to thereby facilitate a management of the client expense account associated with the cache memory includes:

communicating any size adjustment to the cache size of the cache memory based on the determination of the optimal cache size of the cache memory to at least one device over at least one communication channel established by at least one network.