Pegasus is a distributed key-value storage system developed and maintained by Xiaomi Cloud Storage Team, with targets of high availability, high performance, strong consistency and ease of use. The original motivation of this project is to replace Apache HBase for users who only need simple key-value schema but require low latency and high availability. It is based on the open source rDSN framework, and uses modified RocksDB as underlying storage engine. The consensus algorithm it uses is PacificA. Unlike Bigtable/HBase, a non-layered replication archiecture is adopted in pegasus in which an external DFS like GFS/HDFS isn't the dependency of the persistent data, which benefits the availablity a lot. Meanwhile, availablity problems in HBase which result from Java GC are totally eliminated for the use of C++.