Disk drive mapping entries of a defect list into clusters

A method of operating a disk drive, the disk drive comprising a first disk surface and a second disk surface, wherein each disk surface comprises a plurality of data tracks, and a first head actuated over the first disk surface, and a second head actuated over the second disk surface, the method comprising:

• generating a defect list comprising a plurality of entries, wherein each entry comprises a track number comprising a defect;
• identifying a first cluster across the first and second disk surfaces, wherein a maximum data track number X1 in the first cluster on the first disk surface is less than a maximum data track number Y1 in the first cluster on the second disk surface;
• identifying a second cluster across the first and second disk surfaces, wherein a maximum data track number X2 in the second cluster on the first disk surface is less than a maximum data track number Y2 in the second cluster on the second disk surface;
• selecting an entry from the defect list in response to X1;
• and
• mapping the selected entry of the defect list into the second cluster.