Robinhood Policy Engine is a multi-purpose tool for managing the content of large filesystems. It can audit filesystem content, perform accounting, remove old unused files according to admin-defined policies, show customizable alerts based on file properties, backup data to external storage, and more. It has advanced capabilities for Lustre filesystems. It leverages OST usage, and lists or purges files per OST, with policy criteria based on pools and OST index. It can also process MDT changelogs with Lustre v2. Originally developped for HPC, it has been designed to perform all of its tasks in parallel, so it is particularly adapted for running on large filesystems with millions of entries and petabytes of data. But you can nonetheless take advantage of all of its features for managing smaller filesystems.
Parrot and Chirp are user-level tools that make it easy to rapidly deploy wide area filesystems. Parrot is the client component: it transparently attaches to unmodified applications, and redirects their system calls to various remote servers. A variety of controls can be applied to modify the namespace and resources available to the application. Chirp is the server component: it allows an ordinary user to easily export and share storage across the wide area with a single command. A rich access control system allows users to mix and match multiple authentication types. Parrot and Chirp are most useful in the context of large scale distributed systems such as clusters, clouds, and grids where one may have limited permissions to install software.
libguestfs is a set of tools for accessing and modifying virtual machine (VM) disk images. You can use this for viewing and editing files inside guests, scripting changes to VMs, monitoring disk used/free statistics, P2V, V2V, performing partial backups, cloning VMs, and much more. libguestfs can access nearly any type of filesystem including: all known types of Linux filesystem (ext2/3/4, XFS, btrfs, etc.), any Windows filesystem (VFAT and NTFS), any Mac OS X and BSD filesystems, LVM2 volumes, MBR and GPT disk partitions, raw disks, qcow2, CD and DVD ISO images, SD cards, and dozens more. libguestfs doesn't need root permissions.