A Fan-Out Snapshotting File System
Snapshots allow users to modify the file system, while maintaining the
ability to view the file system precisely as it was when a snapshot was
taken. Snapshots are useful because they provide versioning, and allow
consistent access to an entire tree (e.g., so that backups can be taken
on a live system).
We will build a fan-out stackable snapshotting file system that supports
an arbitrarily large number of snapshots, using Unionfs to provide the
core fan-out infrastructure. When a snapshot is taken, an empty high
priority branch will be inserted into the fan. Any modifications are
made within the new branch, and the original data is preserved in the
the previous branches.
There are three methods of accessing a snapshot. A user may use a
separate name space (e.g., /snapshots/03132003 for March 13, 2003). A
special operator may be used to access the previous snapshot (e.g., ...
will go to the previous snapshot of that directory). Finally, We will
update the VFS to allow one path to have multiple per-entity trees. The
user can run a new utility set-snap that informs Snapshotfs which
view the user or process is using.
Conference and Workshop Papers:
||Name (click for home page)
||Charles P. Wright
||May 2003 - May 2006
||Partner, Senior Software Architect, Illumon (New York, NY)