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Zach Brown
8cea4916df
Previously the only way that pending invalidations would block lock attempts was by invalidation processing being able to set the new mode of the lock. New lock attempts ignored pending invalidations and could effectively postpone invalidation processing indefinitely by unlocking and locking fast enough. This results in visible hangs where a remote lock attempt to inspect an inode can be blocked indefinitely by active use of the inode. The basic fix of having lock attempts wait when there are pending invalidations is simple. But we have to be careful not to cause deadlocks so we only make lock attempts wait when the lock has no other users. This leaves holes where many active users can still delay invalidation but fixing that would require tracking lock ownership. Signed-off-by: Zach Brown <zab@versity.com>
Introduction
scoutfs is a clustered in-kernel Linux filesystem designed to support large archival systems. It features additional interfaces and metadata so that archive agents can perform their maintenance workflows without walking all the files in the namespace. Its cluster support lets deployments add nodes to satisfy archival tier bandwidth targets.
The design goal is to reach file populations in the trillions, with the archival bandwidth to match, while remaining operational and responsive.
Highlights of the design and implementation include:
- Fully consistent POSIX semantics between nodes
- Atomic transactions to maintain consistent persistent structures
- Integrated archival metadata replaces syncing to external databases
- Dynamic seperation of resources lets nodes write in parallel
- 64bit throughout; no limits on file or directory sizes or counts
- Open GPLv2 implementation
Community Mailing List
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