hardware, the need for decentralization is not particularly strong in most cases. The CurveBS core consists of three parts: 1. Metadata Server (MDS) l Manages and stores metadata information Interacts with the chunkServer to read and write data 4. Snapshotcloneserver l Independent of core services l Snapshot data is stored in object storage which supports S3 apis. Therefore, there 1. A CopySet, as the basic unit of a consistent replication group, contains Consensus Module and Log Module. 2. The State Machine corresponds to the chunk in the CurveBS, and it applies the operations

under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2 under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2 under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2

ontainer 实现了btree map和btree set，(Apache)。 google， https://code.google.com/archive/p/cpp-btree/， btree_map , btree_set, btree_multimap, and btree_multiset ，（ ） Apache B+tree 内部结点不保存数据，只有叶子结点保存数据。

●CurveBS对文件系统元数据的操作非常少，对文件系统的要求不高， 所以不需要元数据高性能，这方面PFS也合适10/17/22 6 对PFS的修改 ●基于阿里开源的PFS ●不再基于daemon模式，而是直接使用pfs core api ●依然向外提供管理工具, 例如 pfs ls、cp、rm等 ●增加spdk驱动10/17/22 7 新增PFS接口 ●增加pfs_pwritev和pfs_preadv接口 ●ssize_t

务器架构 • 基于brpc提供restful API的对外http接口 HttpService: • Serivce层面区分上层请求为同步接口调用，还是异步接口调用， 同步接口调用直接调用Core层接口实现功能，异步接口创建Task， 并交由TaskManager调度。 SnapshotService & CloneService: • 任务管理层负责调度SnapshotTask和CloneTask，并向上提供如

parameter. If the number of pending * background requests exceeds this number, the FUSE kernel module will * mark the filesystem as "congested". This instructs the kernel to * expect that queued