Hybrid synchronization using a shadow component includes detecting a first component of a plurality of mirrored components of a distributed data object becoming unavailable. The mirrored components include a delta component (a special shadow component) and a regular mirror (shadow) component. The delta component indicates a shorter history of changes to data blocks of a log-structured file system (LFS) than is indicated by the regular mirror component. During the unavailability of the first component, at least one write I/O is committed by the delta component. The commit is tracked by the delta component in a first tracking bitmap associated with the delta component. Based at least on detecting the first component becoming available, the first component is synchronized with data from the delta component, based at least on changed data blocks indicated in the first tracking bitmap.

In a storage cluster, a producer and a consumer can be remote from each other and have different capabilities. For example, a consumer may be running on a computing node (hereinafter “node”) that operates faster than a node hosting a producer. In addition, network conditions can impact communications to/from the producer and/or the consumer. This environment allows the possibility of a consumer violating sequential access constraints of a file when a producer is writing to the file. This can lead to the consumer reading incorrect data. A file system can ensure compliance with serialization of a concurrently accessed file by obtaining a lock on a subsequent file range before releasing a currently held write lock.

The disclosed technology relates to a system configured to identify a first operation in a first set of operations configured to converge a server state and a file system state, wherein the first operation is not in a second set of operations generated in response to an change to at least one of the server state and the file system state. The system is further configured to cancel the first operation, identify a second operation in both the first set of operations and the second set of operations, and initiate execution of the second operation concurrently with the canceling of the first operation.

Resolving conflicting changes to structured data files. A method includes for a structured data file which has both a generic structure and dialects built on top of the generic structure, for which conflicting changes have been made, and where an original version of the structured data, a first version of the structured data and a second version of the structured data exist, determining a dialect of the structured data. The method further includes, based on the determined dialect performing at least one of merge or diff operations on the original version of the structured data, the first version of the structured data and the second version of the structured data.

A method, article of manufacture, and apparatus for efficient conflict resolution among stateless processes is disclosed. In some embodiments, a file system view request is sent to a process manager. A check is then made to ensure that a connection to the requested file system is available. A stateless process to interact with the file system is created, a stateless process to display the file system is created, and a state machine to check the validity of operational requests to be performed on the file system is also created. A display is then used to select one conflict resolution mechanism. A plurality of operational requests to interact with the file system is sent to the process manager. For each operational request, the state machine is used to check for valid requests. The valid requests are then performed. For each invalid operational request, the selected conflict resolution mechanism is used to determine whether to terminate or perform the invalid operational request. In some embodiments, software components are removed from the file system. In some embodiments, software components are added to the file system.

Disclosed are a method and apparatus for reading data in a distributed file system in which a client and a server are separated. In the method and apparatus, a prefetching operation is performed to provide a continuous read function with high performance even in the distributed file system so that an optimum continuous read function of a local file system within the client may be effectively supported when an application program of the client requests continuous reading on a file (or chunk).

A client can allocate and reassociate unique identifiers to local content items associated with an account at a content management system, and use the unique identifiers to commit operations for the content items on the content management system. For example, a client can create a content item and determine the content item does not have an identifier from the content management system. The client obtains an identifier for the content item and asks the content management system to verify a uniqueness of the identifier. When the identifier is unique, the client adds a node corresponding to the content item to a local tree representing a state at the client of content items associated with the account, and uploads the content item with the identifier to the content management system. When the identifier is not unique, the client obtains a new identifier for the content item.

A manager program for managing virtual machines includes a process which receives a notification message indicating an occurrence of an event affecting a data storage unit in a data storage system that supports a shared file system. The notification message might have come from a virtual machine host or resulted from a hardware reconfiguration. The manager program then determines whether another virtual machine host is sharing the data storage unit. The manager program might make this determination by polling each of the virtual machine hosts it manages or by checking information previously collected and stored in a database. If another virtual machine host is sharing the data storage unit, the manager program sends a refresh message to that virtual machine host that causes the virtual machine host to update information relating to the data storage unit in a cache associated with the virtual machine host.

A collaborative work tool configured to determine similarity between an input provided by a user and content already received by the collaborative work tool. If a similarity is determined, the collaborative work tool can provide a visual indication to the user to alert the user that the user may be entering redundant data.

The invention provides in some aspects an improved method for transfer of digital media objects that includes storing a digital file on a first digital data device and migrating that digital file to a second digital data device by repeating a plurality of times the steps of: (i) transferring to a second digital data a respective piece of the digital file, (ii) storing that respective piece of the digital file on the second digital data device. The foregoing are effected so that no respective piece of the digital file is concurrently stored on the first and second digital data devices and/or, more generally, so that any same portion of the digital file that is concurrently stored on the first and second digital data devices comprises not more than an insubstantial amount of the digital data file. Methods and apparatus according to the invention can be used for the (re)sale, lending, streaming or other transfer of digital music, digital books and other digital media objects.