Distributed fine-grained enhancements for distributed table driven I/O mapping

A method for performing a write operation to a virtual storage segment mapped to first physical segment while the first physical storage segment is unavailable, the method comprising:

• identifying blocks in the first physical segment that would be affected by the write operation;
• storing a record of identified blocks;
• writing to a second physical segment;
• and
• remapping the virtual storage segment to the second physical segment for one or more of the identified blocks.

A storage system comprising:

• a first physical storage segment;
• a second physical storage segment;
• and
• a bitmap representing storage blocks in the first physical storage segment,
• wherein a first input/output (I/O) operation occurs to the first physical storage segment unless the first physical storage segment is unavailable, and
• wherein the first I/O operation occurs to the second physical storage segment when the first physical storage segment is unavailable and the bitmap designates the storage blocks in the first physical storage segment that would have been affected by the first I/O operation.