摘要:
A file server system having solid-state drive primary storage and magnetic disk drive secondary storage aggressively moves newly created files from the primary storage to selected file systems in the secondary storage to match expected access patterns upon the files to different configurations of the file systems and for load balancing upon the file systems in the secondary storage. Upon read access to a file that has been moved to the secondary storage, or upon migration of a newly created file that was read in primary storage after creation, a corresponding stub file containing file mapping metadata is created in the primary storage. The file mapping metadata in the stub file maps the extent of the file to logical storage addresses in the secondary storage.
摘要:
When a directory tree is migrated from a source file system to a target file system, the directories of the directory tree are retained in the source file system, and handle translation entries are substituted for the regular data files of the directory tree in the source file system. The handle translation entries provide new file handles for the regular data files when the source file system is accessed with old file handles of the regular data files. For example, each handle translation entry includes the old file handle, a file system identifier, and the new file handle. The old file handle provides verification of the file handle being used for accessing the handle translation entry, and the file system identifier identifies the target file system in which the new file handle is valid.
摘要:
A protected file is retained in secondary storage for a retention period, and a corresponding stub file is retained in primary storage for the retention period. The stub file retains attributes of the file indicating a location of the file data in the secondary storage and indicting that the stub file is to be retained for the retention period. A system administrator may instruct a primary file server that a secondary file server supports retention based protection and it is desired to protect stub files corresponding to protected files that are migrated to the secondary file server. The primary file server may request the secondary file server to return a protection status of the file after migration. This enables automatic policy-based migration to both file level retention (FLR) and non-FLR retention protected secondary storage from diverse applications accessing FLR or non-FLR files in the primary storage.
摘要:
A hierarchical storage system is constructed from file servers and a policy engine server by building upon a file migration service. Offline attributes are added to file system inodes in a primary file server, file system parameters are added in the primary server, an offline read access method field is added to a connection database, and the primary file server is programmed to use these attributes and parameters for selecting a particular method (such as a partial read migration or a pass through read method) for read access to an offline file. In this fashion, the primary file server is provided with flexibility for selecting a particular one of a number of migration methods depending on various conditions, in order to improve the trade-off between the cost of storage and delay in file access.
摘要:
A hierarchical storage system includes file servers and a policy engine server. Offline attributes are added to file system inodes in a primary file server, file system parameters are added in the primary server, offline read and write access method fields are added to a connection database, and the primary file server uses these attributes and parameters for selecting a particular read method or write method for access to an offline file or section of an offline file. The write methods follow a “write recall full” policy, a “pass-through write” policy, a “pass-through multi-version” policy, or a “directory write pass-through” policy. The pass-through multi-version policy results in a new offline version of a file each time that a client opens and writes to a multi-version file. The directory write pass-through policy results in a new offline file when a file is created within a write pass-through directory.
摘要:
Directory attributes are provided so that the time for creating an incremental backup of a file system by a scan of the file system tree is proportional generally to the number of files that change between backups instead of the number of files in the file system. A tree modification attribute indicates whether or not any file in a directory tree has changed since the last backup. If no file has changed in the directory tree, then the entire tree is skipped during the scan for changed files. In addition, a list is compiled of the files in the directory that represent branches having at least one changed file, so that the list is scanned instead of the directory entries. When a file is changed for the first time since the last backup, the file is queued so that the directory attributes are updated in a background process.
摘要:
Needless migration of duplicate file data is avoided by recording in a database a record of migration of a first instance of a replicated file from a source file server to a target file server. When migrating a subsequent instance of a replicated file to the target file server, the database is searched for a record of replication of a first instance of the replicated file to the target file server. If such a record is found, the subsequent instance is replicated by sending from the source file server to the target file server attributes of the subsequent instance of the replicated file and an identification of the previously migrated data of the replicated file without re-transmission of the previously migrated data of the replicated file.
摘要:
A file server having a redundant data elimination store responds to requests from clients for copies of space-reduced files. For reduced storage requirements and reduced processing time, a baseline version of unshared data blocks is created in the file server, and then the baseline version is space reduced by conversion to a stub version of shared data blocks, and then the file server responds to a request from a client for creation of one or more space-reduced copies by cloning the stub version. The file server may also respond to a request for creation of a modified space-reduced copy having specified data written at a specified offset. For example, the file server creates a respective modified copy of a virtual server image file for use by each client of the file server.
摘要:
A read-write snapshot copy facility is constructed from a hierarchical storage management facility. The read-write snapshot copy file system initially comprises stub files pointing to the files in a read-only snapshot copy file system. When an application writes to a file in the read-write snapshot copy, the read-write snapshot copy facility migrates a copy of the file to replace the stub file, and then writes to the migrated file. Because the read-write snapshot copy facility references the files in the read-only snapshot file system in a network namespace using standard protocols such as NFS or CIFS, the read-write snapshot copy facility permits referencing of distributed read-only snapshot file systems in an open (heterogeneous) network environment, and the read-write snapshot copy is scalable by linking the read-write snapshot copy facility to multiple file servers containing read-only snapshot file systems.