Patent attributes
According to the prior art load distribution method, there was a drawback in that the time required from discovery of increase of load to the completion of countermeasures was long. In particular, upon receiving migration of data from other file devices, it was necessary to equalize not only the load accompanying normal processes but also the load accompanying the data migration processes. In a file system receiving migration of data from a plurality of file devices, a plurality of virtual NAS (VNAS) is provided within the file storage subsystem, and an associated VNAS for executing data migration from file devices and accesses from clients is respectively associated with each file storage subsystem. Then, the state of each VNAS is defined based on the state of progress of data migration in the file storage subsystem. According to the defined state, load distribution among VNAS is performed.
