Abstract: Techniques are described for building, managing, and enforcing nested quota trees in a filesystem of a data storage system using internal filesystem structures. Such integrated, server-based, nested quota trees avoid the management overhead, communication delays, and slowed processing of proxy-based solutions and are thus more efficient and optimal.

Abstract: Embodiments of the present invention provide a quota-based resource management method, computer program product and apparatus for configuring a resource quota for each user entity of a plurality of user entities based on a first policy or a second policy, the first policy indicating that the resource quota is to be configured using a percentage of an amount of resources allowed to be configured with respect to an amount of all resources, the second policy indicating that the resource quota is to be configured using the amount of resources allowed to be configured; and applying the resource quota according to the first policy or the second policy, and can be adapted to dynamic changes of the amount of resources.

Abstract: A technique for managing usage metrics of quota trees in a file system includes storing, in an inode table that lists inodes of the file system, identifiers (IDs) of quota trees to which the inodes belong. To check the usage of a quota tree, the inode table is scanned for any inodes that reference the quota tree ID of that quota tree. All such inodes are identified, and their usage attributes are summed to calculate an overall usage metric for the quota tree as a whole. The improved technique thus avoids the need to scan directory structures on disk.

Abstract: An online tree quota check tool computes quota usage of files in a directory tree while the structure of the directory tree keeps changing due to concurrent write access by other applications and clients. The quota check tool computes the quota usage without interfering with the ongoing file access operations that change the directory content and quota usage. A quota check database keeps track of which files have been checked and which have not, so that each file is checked and its quota usage is accumulated once and only once while directories are moved and directory scans are restarted as a result of the changing directory content. File system operations are modified to synchronize with the online tree quota check. The quota check tool can be single threaded or multi-threaded. A multi-threaded tool dispatches idle directory iteration threads to scan subdirectories in the directory tree.