Abstract: According to one embodiment, a file system (FS) of a storage system is partitioned into a plurality of FS partitions, where each FS partition stores segments of data files. In response to a request for writing a file to the storage system, the file is stored in a first of the FS partitions that is selected based on a time attribute of the file, such that files having similar time attributes are stored in an identical FS partition.

Abstract: In response to a request for accessing a file stored in a storage system, data objects associated with the file are retrieved from a storage device of the storage system. The data objects of the file are cached in a cache memory. An access sequence of the cached data objects within the file is determined based on metadata of the file, where the access sequence represents a sequential order in time of accessing the cached data objects within the file. In response to a request for cache space reclamation, one or more cached data objects are identified whose next access is a farthest in time from a data object currently being accessed amongst the cached data objects based on the access sequence of the data objects. The identified data objects are evicted from the cache memory whose next access is a farthest amongst the cached data objects.

Abstract: According to one embodiment, in response to a request for verifying a first prime representing a consistent point of a file system of a storage system having a plurality of storage units, each of a plurality of prime segments collectively representing the first prime is examined to determine whether the corresponding prime segment has been previously verified. Each of the prime segments is stored in one of the storage units, respectively. At least a first of the prime segments that has not been previously verified is verified, without verifying a second of the prime segments that has been previously verified. The first prime, when at least the first prime segment has been successfully verified, can be used to construct the consistent point of the file system.

Abstract: Techniques for reducing overheads of primary storage while transferring modified data are described. According to one embodiment, in response to a request at a primary storage for a backup of a plurality of data blocks, a snapshot of the plurality of data blocks is captured, wherein the snapshot represents a consistent state of the plurality of data blocks. Then a set of data block of the captured snapshot that are to be copied to a secondary storage is identified and the identified set of data blocks are transferred to a secondary storage over a network. In response to receiving data to be written to a first data block at the first primary storage during the transfer, current contents of the first data block is preserved if the first data block is in identified set of data blocks, and the received data is committed to the first data block.

Abstract: A system for storing files comprises a processor and a memory. The processor is configured to break a file into one or more segments; store the one or more segments in a first storage unit; and add metadata to the first storage unit so that the file can be accessed independent of a second storage unit, wherein a single namespace enables access for files stored in the first storage unit and the second storage unit. The memory is coupled to the processor and configured to provide the processor with instructions.

Abstract: A method, article of manufacture, and apparatus for transferring data from a source tier to a target tier. In some embodiments, this may include dividing an object stored in the source tier into a plurality of segments, determining if the target tier is missing at least one of the segments, writing the missing segments to the target tier, and deleting the object from the source tier. In some embodiments, the object's metadata is updated to indicate that the object is in the target tier.

Abstract: According to one embodiment, a request is received for obtaining a consistent point of data stored in a file system of a storage system having a plurality of storage units. In response to the request, retrieving a prime dependency list from a first prime segment stored in a first of the storage units, where the prime dependency list includes information identifying at least a second prime segment stored in a second of the storage units. The first and second prime segments collectively form a prime segment representing a consistent view of the file system. Each of the prime segments listed in the prime dependency list is ascertained in an attempt to generate the consistent point of data.

Abstract: According to one embodiment, recovering file systems without a replica is described. In one example, a method includes discovering an error in a first storage partition of the file system containing a current version of a namespace metadata, finding a second storage partition containing a most recent copy of the namespace metadata, and restoring the found copy of the namespace metadata from the second storage partition to the first storage partition for use as a current version of the namespace metadata.

Abstract: According to one embodiment, a file system (FS) of a storage system is partitioned into a plurality of FS partitions, where each FS partition stores segments of data files. In response to an input and output (IO) request for accessing a first of the FS partitions, a second of the FS partitions is selected that is currently in a ready state for access. The second FS partition is then removed from the ready state for access. The first FS partition is brought into a ready state for access.

Abstract: A computer-implemented proxy server local to a backup target system performs a backup method for a system supporting a plurality of virtual machines. The backup method includes receiving an initialization of a connection over a network from a backup server identifying the system to backup to the backup target system, establishing a communication connection over the network with the system to backup including identifying an interface for accessing data of the system to backup, receiving an image of the system to backup from the backup server, retrieving a data set corresponding to the image from the system to backup over the network, and writing the data set to a local file in the backup target system.

Abstract: A request is received to determine a consistent point of data stored in a file system of a storage system having storage units. In response to the request, a prime dependency list is retrieved from a first prime segment stored in a first storage unit, the prime dependency list including information identifying at least a second prime segment stored in a second storage unit. The first and second prime segments are identified by a first prime segment identifier (ID) and a second prime segment ID, respectively, which collectively identify a prime representing a first consistent view of the file system. The consistent point of data is determined based the prime segments listed in the prime dependency list, where the consistent point of data represents a file system state at a point in time for restoration of the file system back to a prior known state.

Abstract: Techniques for data migration of a storage system are described herein. According to one embodiment, for at least one of segments of a file to be migrated from a source storage tier to a target storage tier, a fingerprint of the segment is transmitted to the target storage tier. In response to a response received from the target storage tier indicating that the segment has not been stored in the target tier based on the fingerprint, a storage space of the target tier estimated for migrating the file is incremented. One or more segments of the file that have not been stored in the target tier are migrated if the one or more segments of the file fit in the target storage tier based on the estimated storage space of the target tier.

Abstract: Data objects of a file are cached in a cache memory of a storage system. An access sequence of the cached data objects is determined based on metadata of the file. In response to a request for cache space reclamation, a data object is evicted from the cache memory whose next access is a farthest amongst the cached data objects based on the access sequence of the data objects.

Abstract: Systems and methods are described for backing up files and directories using a common backup format. The files and directories may be represented by objects within a data stream constructed using the common backup format. The data streams may be traversed and updated using a size tree such that modifications are made to individual objects within the data streams without complete traversal. This process results in efficient management of storage systems as read and write operations are not dependent on exhaustive traversal of data streams.

Abstract: According to one embodiment, a file system (FS) of a storage system is partitioned into a plurality of FS partitions, where each FS partition stores segments of data files. In response to a request for writing a file to the storage system, the file is stored in a first of the FS partitions that is selected based on a time attribute of the file, such that files having similar time attributes are stored in an identical FS partition.

Abstract: A VM management server receives a request from a backup application server to back up a first VM. The VM management server determines a first of the host systems based on the request, wherein the first host system hosts the first VM. A first request is transmitted from the VM management server to a VMM of the first host system hosting the first VM via a VM application programming interface (VM API) over a network. The first request requests the VMM to capture a VM snapshot representing a consistent state of the first VM. In response to determining that the consistent state of the VM has been captured, a second request is transmitted to a first storage system associated with the first host system to send one or more VM disk images associated with the consistent state of the first VM to a second storage system over the network.

Abstract: Systems and methods are described for backing up files and directories using a common backup format. The files and directories may be represented by objects within a data stream constructed using the common backup format. The data streams may be traversed and updated using a size tree such that modifications are made to individual objects within the data streams without complete traversal. This process results in efficient management of storage systems as read and write operations are not dependent on exhaustive traversal of data streams.

Abstract: A method, article of manufacture, and apparatus for transferring data from a source tier to a target tier. In some embodiments, this may include dividing an object stored in the source tier into a plurality of segments, determining if the target tier is missing at least one of the segments, writing the missing segments to the target tier, and deleting the object from the source tier. In some embodiments, the object's metadata is updated to indicate that the object is in the target tier.

Abstract: A request is received to read a portion of a file from the storage system. In response to the request, future requests to the file are predicted based in part on the received request and metadata of the file. Access of a subsequent portion of the file is optimized based on the predicted future requests and the data contained in the portion of the file is then returned.

Abstract: A VM management server receives a request from a backup application server to back up a first VM. The VM management server determines a first of the host systems based on the request, wherein the first host system hosts the first VM. A first request is transmitted from the VM management server to a VMM of the first host system hosting the first VM via a VM application programming interface (VM API) over a network. The first request requests the VMM to capture a VM snapshot representing a consistent state of the first VM. In response to determining that the consistent state of the VM has been captured, a second request is transmitted to a first storage system associated with the first host system to send one or more VM disk images associated with the consistent state of the first VM to a second storage system over the network.