  Cloud storage systems have been introduced to provide a scalable, secure,
reliable, and highly available data storage environment for the organizations
and end-users. Therefore, the service provider should grow in a geographical
extent. Consequently, extensive storage service provision requires a
replication mechanism. Replication imposes many costs on the cloud storage,
including the synchronization, communications, storage, etc., costs among the
replicas. Moreover, the synchronization process among replicas is a major
challenge in cloud storage. Therefore, consistency can be defined as the
coordination among the replicas. In this paper, we propose an extension to the
strict timed causal consistency by adding the considerations for the monetary
costs and the number of violations in the cloud storage systems and call it the
extended strict timed causal consistency. Our proposed supports monotonic read,
read your write, monotonic write, and write follow read, models by taking into
account the causal relations between users' operations, at the client-side.
Besides, it supports timed causal at the server-side. We employed the Cassandra
cloud database that supports various consistencies such as all, one, quorum,
etc. Our method performs better in reducing staleness rate, the severity of
violations, and monetary cost in comparison with all, one, quorum, and causal.
