Efficient resilience in a metadata paging array for in-flight user data

An apparatus comprising:

• a plurality of managed drives;
• a plurality of interconnected computing nodes that manage access to the managed drives and present a logical volume to a host;
• and
• a relocator, responsive to a failure occurring during movement of an allocation unit of data of the logical volume from a source device to a target device, to:
• determine that logical volume metadata for the allocation unit in volatile memory is consistent with logical volume metadata for the allocation unit in non-volatile storage, determine that target device metadata for the data in volatile memory is consistent with target device metadata for the data in non-volatile storage, determine that linkage between logical volume metadata for the allocation unit and target device metadata for the data is reciprocal, and recover the data from the target device.

A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for using a computer system to recover data that is in-flight during a failure, the method comprising:

• in a storage system in which an allocation unit of data of a logical volume is being moved from a source device to a target device when a failure occurs, recovering the data by:
• determining that logical volume metadata for the allocation unit in volatile memory is consistent with logical volume metadata for the allocation unit in non-volatile storage;
• determining that target device metadata for the data in volatile memory is consistent with target device metadata for the data in non-volatile storage;
• determining that linkage between logical volume metadata for the allocation unit and target device metadata for the data is reciprocal;
• and
• recovering the data from the target device.