Error recovery for input/output operations

1. A method, comprising:

tuning error recovery in a storage device by:

receiving a user command to set an error recovery level of the storage device;

propagating the user command down the layers of the input/output stack;

as the user command is propagated, selectively modifying the user command;

when the command indicates one state, enabling limited error recovery for failed input/output operations; and

when the command indicates another state, enabling a higher level of error recovery for failed input/output operations.

2. The method of claim 1 , wherein receiving a command to set the error recovery level comprises receiving a command over a management interface.

3. A method, comprising:

receiving a request for an input/output operation;

determining an error recovery level to use if the input/output operation fails;

embedding a state signal that indicates the error recovery level into a command to execute the input/output operation;

issuing the command;

propagating the command down an input/output stack to a storage device; and

selectively modifying the command as the command propagates down the layers of the input/output stack.

4. The method of claim 3 , wherein embedding a state signal comprises embedding a state signal in an input/output command issued to a device driver.

5. The method of claim 4 , wherein propagating the command comprises passing the command from the device driver to the storage device.

6. The method of claim 3 , wherein embedding a state signal comprises setting a value of a bit in an input/output command to one of two states with one state for a high level of error recovery and another state for a lower level of error recovery.

7. The method of claim 3 , wherein embedding a state signal comprises setting a value of N bits in an input/output command to one of up to 2 N states associated with selectable levels of error recovery.

8. The method of claim 3 , wherein determining an error recovery level comprises determining whether redundant data is available on a separate storage device.

9. A machine-readable medium having instructions stored thereon for performing a method for executing an input/output operation with a selectable error recovery level, the method comprising

receiving a request for an input/output operation from an application program;

determining whether the requested input/output operation relates to redundant data controlled by a logical storage manager;

generating a state signal for use in error recovery if the input/output operation fails, wherein the state signal is based on the determination as to the existence of redundant data;

embedding the state signal into a field of a command to execute the input/output operation;

issuing the command;

propagating the command down an input/output stack from the logical storage manager to a storage device; and

selectively modifying the command as the command propagates down the layers of the input/output stack.

10. A system comprising:

a host system running an operating system and at least one application;

at least one storage device, coupled to the host system, for storing data;

wherein the operating system includes at least one device driver, in communication with the at least one storage device, and

wherein the operating system selectively tunes the level of error recovery associated with an input/output request as the request is propagated down the input/output stack between the application and the storage device.

11. The system of claim 10 , wherein the operating system includes a logical volume manager layer that determines whether to alter an embedded state signal in an input/output request from the at least one application before propagating the input/output request to the at least one device driver.

12. The system of claim 11 , wherein the at least one device driver further determines whether to alter the embedded state signal in the input/output request from the logical volume manager layer before propagating the input/output request to the at least one storage device.