1. A method for storing data in a data processing system having at least one host computer and at least one storage device, the method comprising: directing that first modified data in a first cluster be stored in a preserved area of memory of the second cluster in a normal operating mode; directing that second modified data in a second cluster be stored in a preserved portion of memory of the first cluster in the normal operating mode; directing that the first modified data be stored in a first storage device in a power failure mode; directing that the second modified data be stored in a second storage device in the power failure mode; directing that the first modified data be transferred from the preserved area of the second cluster to the second storage device in the power failure mode; and directing that the second modified data be transferred from the preserved area of the first cluster to the first storage device in the power failure mode; whereby, if one of the first or second cluster fails to recover after a power failure, the modified data from the failed cluster is available through the other cluster.