Abstract: A method for data storage includes assigning multiple different portions of a given object, which is stored in non-volatile storage, for access by multiple respective software modules running on one or more processors. Storage operations are performed by the software modules in the portions of the given object. Respective local values, which are indicative of most recent times the storage operations were performed in the given object by the respective software modules, are updated by the software modules. A global value is updated for the given object, by consolidating updates of the local values performed by the software modules.

Abstract: A method for data storage includes assigning multiple different portions of a given object, which is stored in non-volatile storage, for access by multiple respective software modules running on one or more processors. Storage operations are performed by the software modules in the portions of the given object. Respective local values, which are indicative of most recent times the storage operations were performed in the given object by the respective software modules, are updated by the software modules. A global value is updated for the given object, by consolidating updates of the local values performed by the software modules.

Abstract: A method includes, in a computing system that runs clients on multiple interconnected compute nodes, running on the compute nodes respective virtual switches and respective virtual heads. Each client is provisioned to direct file access commands using one or more access protocols to a respective virtual head running on the compute node on which the client runs, via a respective virtual switch running on the compute node on which the client runs. The file access commands issued by the clients are executed by communicating among the virtual heads using an inter-node communication protocol that is independent of the access protocols used by the clients.

Abstract: A method includes, in a computing system that runs clients on multiple interconnected compute nodes, running on the compute nodes respective virtual switches and respective virtual heads. Each client is provisioned to direct file access commands using one or more access protocols to a respective virtual head running on the compute node on which the client runs, via a respective virtual switch running on the compute node on which the client runs. The file access commands issued by the clients are executed by communicating among the virtual heads using an inter-node communication protocol that is independent of the access protocols used by the clients.

Abstract: A method includes receiving data objects for storage in at least one or more first storage devices characterized by a first write endurance, and one or more second storage devices characterized by a second write endurance that is lower than the first write endurance. Respective write-activity levels are estimated for the data objects. For each data object, a choice is made whether to store the data object in the first storage devices or in the second storage devices based on an estimated write-activity level of the data object. The data object is stored in the chosen storage devices.

Abstract: A method for data storage includes running on multiple interconnected compute nodes respective virtual heads that collaboratively store files in persistent storage. In response to receiving in an initiator virtual head a request to write at least a portion of a given file, the initiator virtual head selects one or more destination virtual heads for storing the portion. The portion is sent from the initiator virtual head to the selected destination virtual heads, and a notification of the selected destination virtual heads is sent to an owner virtual head, which has been assigned to own metadata of the portion. In the destination virtual heads, the portion received from the initiator virtual head is cached, and committed to the persistent storage only in response to receiving a commit instruction from the owner virtual head.

Abstract: A method includes receiving data objects for storage in at least one or more first storage devices characterized by a first write endurance, and one or more second storage devices characterized by a second write endurance that is lower than the first write endurance. Respective write-activity levels are estimated for the data objects. For each data object, a choice is made whether to store the data object in the first storage devices or in the second storage devices based on an estimated write-activity level of the data object. The data object is stored in the chosen storage devices.

Abstract: A method for data storage includes running on multiple interconnected compute nodes respective virtual heads that collaboratively store files in persistent storage. In response to receiving in an initiator virtual head a request to write at least a portion of a given file, the initiator virtual head selects one or more destination virtual heads for storing the portion. The portion is sent from the initiator virtual head to the selected destination virtual heads, and a notification of the selected destination virtual heads is sent to an owner virtual head, which has been assigned to own metadata of the portion. In the destination virtual heads, the portion received from the initiator virtual head is cached, and committed to the persistent storage only in response to receiving a commit instruction from the owner virtual head.

Abstract: A method includes, in a computing system that runs clients on multiple interconnected compute nodes, running on the compute nodes respective virtual switches and respective virtual heads. Each client is provisioned to direct file access commands using one or more access protocols to a respective virtual head running on the compute node on which the client runs, via a respective virtual switch running on the compute node on which the client runs. The file access commands issued by the clients are executed by communicating among the virtual heads using an inter-node communication protocol that is independent of the access protocols used by the clients.