Data storage subsystem with fairness-driven update blocking

A method for managing updates submitted by host applications for storage by a data storage system that includes a primary subsystem and a mirrored secondary subsystem, the primary subsystem including data storage containing multiple data items, the method comprising the operations of:

• receiving update requests, each update request including update data and identification of an associated data item in the data storage to be updated by the update data;
• for each received update request, consulting an update record to determine whether past update activity of the associated data item exceeds a prescribed level, and
• if not, storing the update in an update buffer and advancing the update record;
• if so, consulting a rejection record to determine whether past rejection of updates to the associated data item exceeds a predetermined level, and
• if so, storing the update in the update buffer and advancing the update record;
• if not, rejecting the update and advancing the rejection record.

A method of managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage devices, where the primary subsystem receives update requests from one or more hosts, each update request including update data and specification of one of the primary storage devices, and where responsive to each update request the primary subsystem initially buffers the update data in a primary subsystem sidefile and thereafter copies the buffered update data to the specified primary storage device and also to a counterpart secondary device, the method comprising the operations of:

• tracking update activity according to specified primary storage device;
• performing fairness-driven update regulation, comprising:
• for update requests specifying primary storage devices with a prescribed level of update activity, preventing storage of these update requests in the sidefile;
• and
• for update requests specifying primary storage devices with less than the prescribed level of update activity, permitting these update requests to continue to fill the sidefile.

A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method for managing updates received at a primary data storage subsystem for duplication at a counterpart secondary storage subsystem, the primary subsystem including an update buffer and a data storage of multiple subparts, where the primary subsystem receives update requests from at least one host, each update request including update data and designation of a corresponding target primary storage subpart, the method comprising the operations of:

• for each subpart, maintaining an update activity indicator representing update activity of that subpart;
• repeatedly evaluating whether update activity for any subpart has exceeded a prescribed threshold;
• and
• for each received update request,
• if the update activity indicator for the update request's target subpart has exceeded the threshold, selectively rejecting the update;
• and
• if the update activity indicator for the update request's designated subpart has not exceeded the threshold, storing the update data in the update buffer.

A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for managing updates submitted by host applications for storage by a data storage system that includes a primary subsystem and a mirrored secondary subsystem, the primary subsystem including data storage containing multiple data items, the operations comprising:

• receiving update requests, each update request including update data and identification of an associated data item in the data storage to be updated by the update data;
• for each received update request, consulting an update record to determine whether past update activity of the associated data item exceeds a prescribed level, and
• if not, storing the update in an update buffer and advancing the update record;
• if so, consulting a rejection record to determine whether past rejection of updates to the associated data item exceeds a predetermined level, and
• if so, storing the update in the update buffer and advancing the update record;
• if not, rejecting the update and advancing the rejection record.

A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method of managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage devices, where the primary subsystem receives update requests from one or more hosts, each update request including update data and specification of one of the primary storage devices, and where responsive to each update request the primary subsystem initially buffers the update data in a primary subsystem sidefile and thereafter copies the buffered update data to the specified primary storage device and also to a counterpart secondary device, the method comprising the operations of:

• tracking update activity according to specified primary storage device;
• performing fairness-driven update regulation, comprising:
• for update requests specifying primary storage devices with a prescribed level of update activity, preventing storage of these update requests in the sidefile;
• and
• for update requests specifying primary storage devices with less than the prescribed level of update activity, permitting these update requests to continue to fill the sidefile.

A logic circuit of multiple interconnected electrically conductive elements configured to perform operations for managing updates received at a primary data storage subsystem for duplication at a counterpart secondary storage subsystem, the primary subsystem including an update buffer and a data storage of multiple subparts, the method comprising the operations of:

• the primary subsystem receiving update requests from at least one host, each update request including update data and designation of a corresponding target primary storage subpart;
• and
• for each subpart, maintaining an update activity indicator representing update activity of that subpart;
• repeatedly evaluating whether update activity for any subpart has exceeded a prescribed threshold;
• and
• for each received update request,
• if the update activity indicator for the update request's target subpart has exceeded the threshold, selectively rejecting the update;
• and
• if the update activity indicator for the update request's designated subpart has not exceeded the threshold, storing the update data in the update buffer.

A logic circuit of multiple interconnected electrically conductive elements configured to perform operations for managing updates submitted by host applications for storage by a data storage system that includes a primary subsystem and a mirrored secondary subsystem, the primary subsystem including data storage containing multiple data items, the operations comprising:

• receiving update requests, each update request including update data and identification of an associated data item in the data storage to be updated by the update data;
• for each received update request, consulting an update record to determine whether past update activity of the associated data item exceeds a prescribed level, and
• if not, storing the update in an update buffer and advancing the update record;
• if so, consulting a rejection record to determine whether past rejection of updates to the associated data item exceeds a predetermined level, and
• if so, storing the update in the update buffer and advancing the update record;
• if not, rejecting the update and advancing the rejection record.

A logic circuit of multiple interconnected electrically conductive elements configured to perform operations for managing updates received at a primary data storage subsystem for managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage devices, where the primary subsystem receives update requests from one or more hosts, each update request including update data and specification of one of the primary storage devices, and where responsive to each update request the primary subsystem initially buffers the update data in a primary subsystem sidefile and thereafter copies the buffered update data to the specified primary storage device and also to a counterpart secondary device, the method comprising the operations of:

• tracking update activity according to specified primary storage device;
• performing fairness-driven update regulation, comprising:
• for update requests specifying primary storage devices with a prescribed level of update activity, preventing storage of these update requests in the sidefile;
• and
• for update requests specifying primary storage devices with less than the prescribed level of update activity, permitting these update requests to continue to fill the sidefile.

A digital data storage subsystem, comprising:

• a backup data storage subsystem;
• a primary data storage subsystem coupled to the backup data storage subsystem and including a controller, an update buffer, and a data storage of multiple subparts, the controller being programmed to perform operations to manage updates received at the primary data storage subsystem for duplication at the secondary storage subsystem, the operations comprising:
• the primary subsystem receiving update requests from at least one host, each update request including update data and designation of a corresponding target primary storage subpart;
• and
• for each subpart, maintaining an update activity indicator representing update activity of that subpart;
• repeatedly evaluating whether update activity for any subpart has exceeded a prescribed threshold;
• and
• for each received update request,
• if the update activity indicator for the update request's target subpart has exceeded the threshold, selectively rejecting the update request;
• and
• if the update activity indicator for the update request's designated subpart has not exceeded the threshold, storing the update data in the update buffer.

A digital data storage subsystem, comprising:

• a backup subsystem;
• a primary subsystem coupled to the backup subsystem and programmed to perform operations to manage updates submitted by host applications for storage by the primary subsystem, the operations comprising:
• the primary subsystem receiving update requests, each update request including update data and identification of an associated data item in the data storage to be updated by the update data;
• for each received update request, consulting an update record to determine whether past update activity of the associated data item exceeds a prescribed level, and
• if not, storing the update in an update buffer and advancing the update record;
• if so, consulting a rejection record to determine whether past rejection of updates to the associated data item exceeds a predetermined level, and
• if so, storing the update in the update buffer and advancing the update record;
• if not, rejecting the update and advancing the rejection record.

A digital data storage system, comprising:

• a backup data storage subsystem including backup storage devices;
• a primary data storage subsystem coupled to the backup data storage subsystem and including a controller, an update buffer, a primary subsystem sidefile, and primary storage devices corresponding to the backup storage devices, the primary data storage subsystem being coupled to one or more hosts for receiving update requests each including update data and specification of one of the primary storage devices, the controller being programmed to perform operations to manage update activity in the data storage system, the operations comprising:
• tracking update activity according to specified primary storage device;
• performing fairness-driven update regulation, comprising:
• for update requests specifying primary storage devices with a prescribed level of update activity, preventing storage of the associated update data in the sidefile;
• and
• for update requests specifying primary storage devices with less than the prescribed level of update activity, permitting these update requests to continue to fill the sidefile.

A digital data storage subsystem, comprising:

• a backup data storage subsystem;
• a primary data storage subsystem, comprising:
• an update buffer;
• a data storage of multiple subparts,
• a controller programmed to receive update requests from at least one host for duplication at the secondary storage subsystem, each update request including update data and designation of a corresponding target primary storage subpart;
• an update activity indicator maintaining a representation of update activity of each subpart;
• a data mover interconnected between the primary and backup subsystems, programmed to remotely manage updates received at the primary storage subsystem, the operations comprising:
• communicating with the controller to obtain reports of update activity;
• repeatedly evaluating whether update activity for any subpart has exceeded a prescribed threshold;
• and
• communicating with the controller to obtain notification of update requests received by the controller, and for each received update request,
• if the update activity indicator for the update request's target subpart has exceeded the threshold, selectively instructing the controller to reject the update;
• and
• if the update activity indicator for the update request's designated subpart has not exceeded the threshold, instructing the controller to store the update data in the update buffer;
• selectively copying update data from the update buffer to the backup subsystem.

A digital data storage subsystem, comprising:

• a backup subsystem;
• a primary subsystem including data storage containing multiple data items;
• a data mover interconnected between the primary and backup subsystems, programmed to mirror data storage of the primary subsystem at the backup subsystem, and to perform operations to manage updates submitted by host applications for storage by the primary subsystem, the operations comprising:
• receiving update requests, each update request including update data and identification of an associated data item in the data storage to be updated by the update data;
• each received update request, consulting an update record to determine whether past update activity of the associated data item exceeds a prescribed level, and
• if not, storing the update in an update buffer and advancing the update record;
• if so, consulting a rejection record to determine whether past rejection of updates to the associated data item exceeds a predetermined level, and
• if so, storing the update in the update buffer and advancing the update record;
• if not, rejecting the update and advancing the rejection record.

A digital data storage system, comprising:

• a backup data storage subsystem including backup storage devices;
• a primary data storage subsystem, comprising:
• a sidefile;
• primary storage devices corresponding to the backup storage devices;
• a controller, programmed to receive update requests from one or more hosts, each update request including update data and specification of one of the primary storage devices,
• a data mover interconnected between the primary and backup subsystems, programmed to remotely manage updates received at the primary storage subsystem, the operations comprising:
• tracking update activity at the primary storage subsystem according to specified primary storage device;
• performing fairness-driven update regulation, comprising:
• for update requests specifying primary storage devices with a prescribed level of update activity, instructing the controller to prevent storage of the associated update data in the sidefile;
• and
• for update requests specifying primary storage devices with less than the prescribed level of update activity, instructing the controller to store the associated update data in the sidefile.

A method of managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage, each storage including multiple data objects, where the system includes a module that receives update requests from one or more hosts, each update request including update data and specification of a corresponding one of the primary storage data objects, the module responsive to each update request to initially buffer the update data and thereafter copy the buffered update data to the primary and secondary storage in association with the specified data object, the method comprising the operations of:

• tracking update activity according to specified primary storage data object;
• performing fairness-driven update regulation, comprising:
• for each update request specifying a primary storage data object demonstrating historical update activity exceeding a prescribed threshold, preventing buffering of update data of said update request;
• and
• for each update request specifying a primary storage data object whose historical update activity does not exceed the prescribed threshold, permitting buffering of update data of said update request.

A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations of managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage, each storage including multiple data objects, where the system includes a module that receives update requests from one or more hosts, each update request including update data and specification of a corresponding one of the primary storage data objects, the module responsive to each update request to initially buffer the update data and thereafter copy the buffered update data to the primary and secondary storage in association with the specified data object, the method comprising the operations of:

• tracking update activity according to specified primary storage data object;
• performing fairness-driven update regulation, comprising:
• for each update request specifying a primary storage data object demonstrating historical update activity exceeding a prescribed threshold, preventing buffering of update data of said update request;
• and
• for each update request specifying a primary storage data object whose historical update activity does not exceed the prescribed threshold, permitting buffering of update data of said update request.

A logic circuit of multiple interconnected electrically conductive elements configured to perform operations for managing update activity in a data storage system that includes a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage, each storage including multiple data objects, where the system includes a module that receives update requests from one or more hosts, each update request including update data and specification of a corresponding one of the primary storage data objects, the module responsive to each update request to initially buffer the update data and thereafter copy the buffered update data to the primary and secondary storage in association with the specified data object, the method comprising the operations of:

• tracking update activity according to specified primary storage data object;
• performing fairness-driven update regulation, comprising:
• each update request specifying a primary storage data object demonstrating historical update activity exceeding a prescribed threshold, preventing buffering of update data of said update request;
• and
• for each update request specifying a primary storage data object whose historical update activity does not exceed the prescribed threshold, permitting buffering of update data of said update request.

A digital data storage system, comprising:

• a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage, each storage including multiple data objects;
• a module configured to receive update requests from one or more hosts, each update request including update data and specification of a corresponding one of the primary storage data objects, the module responsive to each update request to initially buffer the update data and thereafter copy the buffered update data to the primary and secondary storage in association with the specified data object, the module also configured to manage update activity in the data storage system by performing operations comprising:
• tracking update activity according to specified primary storage data object;
• performing fairness-driven update regulation, comprising:
• for each update request specifying a primary storage data object demonstrating historical update activity exceeding a prescribed threshold, preventing buffering of update data of said update request;
• and
• for each update request specifying a primary storage data object whose historical update activity does not exceed the prescribed threshold, permitting buffering of update data of said update request.

A digital data storage system, comprising:

• a primary subsystem and a secondary subsystem, the primary and secondary subsystems including respective primary and secondary storage, each storage including multiple data objects;
• a module configured to receive update requests from one or more hosts, each update request including update data and specification of a corresponding one of the primary storage data objects, the module responsive to each update request to initially buffer the update data and thereafter copy the buffered update data to the primary and secondary storage in association with the specified data object, the module further including means for managing update activity in the data storage system by:
• tracking update activity according to specified primary storage data object;
• performing fairness-driven update regulation, comprising:
• for each update request specifying a primary storage data object demonstrating historical update activity exceeding a prescribed threshold, preventing buffering of update data of said update request;
• and
• for each update request specifying a primary storage data object whose historical update activity does not exceed the prescribed threshold, permitting buffering of update data of said update request.