Abstract: A method for data storage includes specifying a plurality of File Systems (FSs) for use by multiple clients, including assigning to the FSs both respective global identifiers and respective client-specific names. The plurality of FSs is managed using the global identifiers, and files are stored for the clients in the FSs using the client-specific names.

Abstract: A computing system includes multiple compute nodes that include respective processors and respective cache memories. The processors are configured to determine a default compute node in which a given data item is to be cached, to make a decision whether to cache the given data item in the default compute node or in an alternative compute node, based on cache-quality metrics that are evaluated for respective cache memories of the compute nodes, and to cache the given data item in the default compute node or in the alternative compute node, depending on the decision.

Abstract: A data storage apparatus includes an interface for communicating with a backup storage system, and one or more processors. The one or more processors are configured to store a local copy of at least part of a file system represented by hierarchical structure of directories and files, to store a backup copy of the at least part of the file system in the backup storage system, to store a dual Merkle tree that is calculated over the backup copy and includes (i) a metadata Merkle tree including Metadata Merkle-Tree Keys (MD-MTKs) and (ii) a data Merkle tree including Data Merkle-Tree Keys (D-MTKs), and to update the backup copy to match the local copy using the dual Merkle tree.

Abstract: A computing system includes a storage device and a host. The storage device includes a volatile memory and a non-volatile memory, and is configured to receive data for storage in the non-volatile memory, to buffer at least some of the received data temporarily in the volatile memory, and to guarantee that any data, which is not part of a predefined amount of data that was most recently received, has been committed to the non-volatile memory. The host is configured to send the data for storage in the storage device, and, in response to a need to commit given data to the non-volatile memory, to send the given data to the storage device followed by at least the predefined amount of additional data.

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.