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91bbf90f71
The btree_merge code was pinning leaf blocks for all input btrees as it iterated over them. This doesn't work when there are a very large number of input btrees. It can run out of memory trying to hold a reference to a 64KiB leaf block for each input root. This reworks the btree merging code. It reads a window of blocks from all input trees to get a set of merged items. It can take multiple passes to complete the merge but by setting the merge window large enough this overhead is reduced. Merging now consumes a fixed amount of memory rather than using memory proportional to the number of input btrees. 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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