Source cleaning cascaded volumes using write and background copy indicators

摘要

Various systems, processes, and products may be used to source clean cascaded volumes. In particular implementations, a system, process, and product for source cleaning cascaded volumes may include the ability to store a primary volume and a plurality of cascaded backup volumes. The system, process, and product may also include the ability to determine whether a write to one of the backup volumes is due to a background copy being made of another volume in the cascade and adjust a background copy indicator in a volume map for the backup volume if the write is due to a background copy and to determine whether a write to one of the backup volumes is due to a write to another volume in the cascade and adjust a write copy indicator in a volume map for the backup volume if the write is due to a write to another cascaded volume.

主权项

1. A method comprising:
storing a primary volume and a plurality of cascaded backup volumes for the primary volume; determining whether a write to one of the backup volumes is due to a background copy being made of another volume in the cascade; adjusting a background copy indicator in a volume map for the backup volume if the write is due to a background copy of another volume in the cascade; determining whether a write to one of the backup volumes is due to a write to another volume in the cascade; and adjusting a write copy indicator in a volume map for the backup volume if the write is due to a write to another volume in the cascade; and wherein the volume map for each respective backup volume comprises at least two bitmaps, each bitmap including bits that respectively correspond to regions of the volume, one of the bitmaps indicating whether regions contain data due to writes to another volume and one of the bitmaps indicating whether regions contain data due to a background copy of another volume.