1. Scriber- Vibha Goyal Date:- March 03, 2016 Course:- CS 525University of Illinois at Urbana Champaign CalvinFS: Consistent WAN Replication and Scalable Metadata Management for Distributed File Systems

2. Introduction  Consistent WAN replicated Distributed File System.  Metadata management by high throughput distributed database management system.

3. Cons Pros High latency for multiple-file operations. High latency for updates due to consistent replication over WAN. System can handle billion of files. Provides linearizable operations with high availability even in case of datacenter outages. Low memory requirement for metadata per machine. High read and write throughput. No distributed commit protocol required, which reduces latency. Scheduler is deadlock-free. Allows concurrent writes on a same file.

4. Discussion/Comments Evaluation should have been done on more than 300 machines/real world scenario. Too strong claim to handle unlimited number of files. Focus of the work was small files. Is it possible that the benefit of CalvinFS is weakened when the files are larger? Overhead of background process which is doing the compaction? Median and percentile numbers are given for latencies (not average).

5. Thank You