Patent attributes
A storage system and method of operating the storage system is described where the metadata used to access the data stored in a storage device is distributed amongst a plurality of controllers in communication with a user, with each other and with the storage device. Each controller stores at least the metadata needed to access the data relevant to the user at the time, and metadata is updated to respond to internal system activities such as device failures, snapshots, backup operations or the like. To preserve coherence of the metadata, each metadata update is communicated to the other controllers and the storage device. The update is either transmitted to the other controllers and to the storage device and each metadata location is updated, or the update is transmitted to the storage device and each of the controllers is instructed to request an update from the storage device.
