You can read page 8 in  and section VII. EVALUATION in . I hope these will be helpful.
 Hunt, Patrick, et al. "ZooKeeper: Wait-free Coordination for Internet-scale Systems." USENIX annual technical conference. Vol. 8. 2010.
 Junqueira, Flavio P., Benjamin C. Reed, and Marco Serafini. "Zab: High-performance broadcast for primary-backup systems." Dependable Systems & Networks (DSN), 2011 IEEE/IFIP 41st International Conference on. IEEE, 2011.
From: tj5527 [mailto:[EMAIL PROTECTED]]
Sent: 08 January 2018 13:14
To: [EMAIL PROTECTED]
Subject: Write Ahead Log
I heard that ZooKeeper uses Write Ahead Log for preserving operation information, and am interested in how it's implemented. But when checking ZooKeeper confluence wiki and searching the internet, I don't find much related documents. Only a few source files such as FileTxnLog.java that seems to be related with some lines written directly about write ahead log string.https://github.com/apache/zookeeper/blob/5c4e44332e55bbf21ca59583f3e8ca97fc4bb266/src/java/main/org/apache/zookeeper/server/persistence/FileTxnLog.java
Is this the right place to start? What other resources available out there as reference?