# 数据层

- [内存数据](/etcd/arch/shu-ju-ceng/nei-cun-shu-ju.md)
- [索引](/etcd/arch/shu-ju-ceng/nei-cun-shu-ju/b-tree.md)
- [磁盘数据](/etcd/arch/shu-ju-ceng/ci-pan-shu-ju.md)
- [日志](/etcd/arch/shu-ju-ceng/ci-pan-shu-ju/wal.md)
- [快照](/etcd/arch/shu-ju-ceng/ci-pan-shu-ju/snap.md)
- [数据文件](/etcd/arch/shu-ju-ceng/ci-pan-shu-ju/boltdb.md)