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206c24c41f
Readers can read a set of items that is stale with respect to items that were dirtied and written under a local cluster lock after the read started. The active reader machanism addressed this by refusing to shrink pages that could contain items that were dirtied while any readers were in flight. Under the right circumstances this can result in refusing to shrink quite a lot of pages indeed. This changes the mechanism to allow pages to be reclaimed, and instead forces stale readers to retry. The gamble is that reads are much faster than writes. A small fraction should have to retry, and when they do they can be satisfied by the block cache. 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
Please join us on the open scoutfs-devel@scoutfs.org mailing list hosted on Google Groups