Dynamo: Amazon's Highly Available Key-Value Store

Justification :
This paper talks about Amazons new Key/Value storage system called Dynamo.  The author compares Dynamo with many of the present systems and then shows how Dynamo is different from the rest .Primary theme of paper was tradeoff between availability and consistency . Amazon has chosen an always on  eventually consistent model.The paper leverages several techniques such as consistent hashing ,vector clock ,hinted handoff,quorum systems  at a brisk pace. Having been deployed and run at a varied application  environment at Amazon I feel Dynamo is highly successful and meets essentially all the requirements and expectations it was intended to meet.

Summery :
Dynamo is highly available highly scalable key value store.In order to provide In order to provide high availability, the system adopts an eventual consistency model and leverages several techniques like consistent hashing for load balancing , preference list for data replication, hinted handoff for availability , merkel tree for synchronization and vector clock.Along with this the paper also provides a performance analysis of real system application for various issues like data replication and load balancing.

Pros :
a)The paper gives insight into how various different techniques can be combined to form a complex system.
b)Dynamo is a very practicable system.Has a lot of application for real world systems.
c)Dynamo is highly scalable systems following always on ,eventually consistent model.
d)Systems is optimized for 99.9th percentile not average.
Always writable do better customer experience

Cons :
a)ACID properties compromised.
b)There is no security in system and all the nodes assumed to be trusted.
c)In order to make vector clock scalable author truncates oldest value resulting in reconciliation problems which author ignores saying its not surfaced in production.
d)Dynamo considers heterogeneity as one of the design principles but in the experimental part they have carried out their experiment on all homogeneous machines.