1. A method to assign a premigration pseudotime attribute and a stubbing pseudotime attribute to a logical volume, comprising the steps of: maintaining a logical volume in a first information storage medium at a first time; defining a plurality of host requests; defining a plurality of pseudotime ranges, where each of said pseudotime ranges is associated with a different one of said host requests; determining if a user provides a host request for said logical volume; operative if said user provides a host request for said logical volume, assigning to said logical volume a premigration pseudotime attribute, and a stubbing pseudotime attribute, comprising a time within the pseudotime range associated with that host request; operative if said user does not provide a host request for said logical volume, assigning to said logical volume said first time as said premigration pseudotime attribute, and said first time as said stubbing pseudotime attribute; and saving said premigration pseudotime attribute and said stubbing pseudotime attribute.