Retaining shadow copy data during replication

In a computerized system in which a backup server applies data backups and corresponding updates to one or more backup volumes, a method of determining available shadow copy storage space in the one or more backup volumes to thereby apply data updates received from a production server without deleting valid shadow copy data, comprising:

• an act of receiving one or more data changes from a production server;
• an act of assigning a standard value to each of the one or more data changes in an initial set;
• a step for calculating an amount of available shadow copy storage space in a backup volume, such that the amount is underestimated in order to preserve valid shadow copies stored in the backup volume;
• an act of identifying that a standard value for each of the one or more data changes is less than the calculated amount of the available shadow copy storage space in the backup volume;
• and
• an act of applying each of the one or more data changes to the backup volume, such that valid shadow copies remain in the shadow copy storage volume prior to expiration.

In a computerized system in which a backup server applies data backups and corresponding updates to one or more backup volumes, a computer program product having computer-executable code stored thereon that, when executed, cause one or more processors in the backup server to perform a method comprising the following:

• an act of identifying a set of one or more data changes at a production server;
• a step for determining a total size of changes in the set that are to be applied to a shadow copy storage volume, such that the total size of changes are one of accurately determined or overestimated;
• an act of identifying a size of available shadow copy storage space in the shadow copy storage volume;
• and
• a step for applying the set of one or more data changes to the identified available shadow copy storage space such that valid shadow copies remain in the shadow copy storage volume prior to expiration.