Abstract: A system is disclosed. A node may include a resource. A lock manager may include storage for a data structure for a lock. The data structure may include a first identifier for the resource, a second identifier for an application, and a status for the lock.

Abstract: Provided is a method of synchronizing a distributed object store including a plurality of data stores, the method including bringing a first data store of the data stores online after having been offline, choosing a second data store of the data stores, the second data store being online while the first data store was offline, reading, by the first data store, an entry from a catch-up log, and performing a data modification operation corresponding to the entry on the first data store to synchronize the plurality of data stores.

Abstract: A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Abstract: A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Abstract: A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Abstract: A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Abstract: A method of contention-free lookup including mapping a key of a cache lookup operation to determine an expected location of object data, walking a collision chain by determining whether a cache header signature matches a collision chain signature, when the cache header signature does not match, again walking the collision chain, when the cache header signature matches, determining whether a key in the cache header signature matches the key of the cache lookup operation, when the key does not match, reading a cache entry corresponding to the cache lookup operation, and repopulating the cache entry, when the key matches, acquiring an entry lock, and determining whether the key still matches after acquiring the entry lock, when the key still matches finding the object data in the expected location, and when the key no longer matches, releasing the entry lock, and again walking the collision chain.

Abstract: A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Abstract: A method of contention-free lookup including mapping a key of a cache lookup operation to determine an expected location of object data, walking a collision chain by determining whether a cache header signature matches a collision chain signature, when the cache header signature does not match, again walking the collision chain, when the cache header signature matches, determining whether a key in the cache header signature matches the key of the cache lookup operation, when the key does not match, reading a cache entry corresponding to the cache lookup operation, and repopulating the cache entry, when the key matches, acquiring an entry lock, and determining whether the key still matches after acquiring the entry lock, when the key still matches finding the object data in the expected location, and when the key no longer matches, releasing the entry lock, and again walking the collision chain.

Abstract: A method of contention-free lookup including mapping a key of a cache lookup operation to determine an expected location of object data, walking a collision chain by determining whether a cache header signature matches a collision chain signature, when the cache header signature does not match, again walking the collision chain, when the cache header signature matches, determining whether a key in the cache header signature matches the key of the cache lookup operation, when the key does not match, reading a cache entry corresponding to the cache lookup operation, and repopulating the cache entry, when the key matches, acquiring an entry lock, and determining whether the key still matches after acquiring the entry lock, when the key still matches finding the object data in the expected location, and when the key no longer matches, releasing the entry lock, and again walking the collision chain.

Abstract: Provided is a method of synchronizing a distributed object store including a plurality of data stores, the method including bringing a first data store of the data stores online after having been offline, choosing a second data store of the data stores, the second data store being online while the first data store was offline, reading, by the first data store, an entry from a catch-up log, and performing a data modification operation corresponding to the entry on the first data store to synchronize the plurality of data stores.

Abstract: Provided is a method of cache entry management, the method comprising determining, by a cache manager, a level of importance for each of a plurality of cache entries, assigning, by the cache manager, a metadata type for each of the cache entries based upon the determined level of importance, determining, by the cache manager, a frequency of access of each of the cache entries, generating, by the cache manager, a heat map based upon the determined frequency of access of the cache entries, and determining, by the cache manager, which one of at least two of the cache entries to evict based upon the respective metadata types and the respective frequencies of access.

Abstract: In one embodiment, a solution is provided wherein a volume hierarchy may be received at a network device in a storage area network. Once the network device is ready to apply the volume hierarchy, a message so indicating may be sent. Later, a command to apply the volume hierarchy may be received and the volume hierarchy may be applied so that the network device processes IOs using the volume hierarchy.

Abstract: In one embodiment, a solution is provided wherein a volume hierarchy may be received at a network device in a storage area network. Once the network device is ready to apply the volume hierarchy, a message so indicating may be sent. Later, a command to apply the volume hierarchy may be received and the volume hierarchy may be applied so that the network device processes IOs using the volume hierarchy.

Abstract: In one embodiment, a solution is provided wherein a volume hierarchy may be received at a network device in a storage area network. Once the network device is ready to apply the volume hierarchy, a message so indicating may be sent. Later, a command to apply the volume hierarchy may be received and the volume hierarchy may be applied so that the network device processes IOs using the volume hierarchy.