Who we are Bitrock is a high-end consulting and system integration company, strongly committed to offering cutting-edge and innovative solutions. Our tailored consulting services enable our clients to preserve the value of legacy investments while migrating to more efficient systems and infrastructure. We take a holistic approach to technology: we consider each system in its totality, as a set of interconnected elements that work together to meet business needs. We thrive on overcoming challenges to help our clients reach their goals, by supporting them in the following areas: Data, AI & ML Engineering; Back-end Engineering, Platform Engineering, Front-end Engineering, Product Design & UX Engineering, Mobile App Development, Quality Assurance, FinOps, Governance. The effectiveness of our solutions also stems from partnerships with key technology vendors, like HashiCorp, Confluent, Lightbend, Databricks, and Meterian. Who we are looking for We are looking for a Senior Data Architect Freelance to lead the evolutionary migration of a production Apache Cassandra 3.11 cluster (approx. 29 TiB of unique data) to Cassandra 5.0, using a parallel-cluster architecture with zero downtime. The role You will be the technical reference for the project and the design authority on everything related to data. You will work closely with the client, a team of DevOps engineers and backend developers, and the project manager, from the initial assessment through cutover and the subsequent support phase. Responsibilities
• Lead the assessment of the existing cluster: analysis of SSTables, partitions, tombstones and workload, performance baseline, mapping of read and write flows.
• Design the target data model (DDL, bucket granularity, compaction strategies such as TWCS and UCS, TTL and differentiated retention), backing your choices with measured data.
• Define the capacity model and hardware sizing of the new cluster, including a rack-aware topology across three failure domains.




• Provide technical direction for the historical data migration: transformation specification, preservation of writetime and TTL, multi-level validation plan.
• Support the backend team in adapting application queries to the new data model.
• Define and verify acceptance criteria: p95 latencies, data integrity, rollback procedures.
• Write and present design documents, migration plans and technical reports to the client.
• During the maintenance phase, act as third-level escalation on Cassandra and data architecture, estimating and validating Change Requests. Requirements
• Proven experience in technical roles on projects using Apache Cassandra in production.
• In-depth knowledge of Cassandra data modelling, particularly for time series and IoT data.
• Hands-on experience with Cassandra operations: compaction, repair (Cassandra Reaper or equivalent), backup and restore, JVM and storage tuning, troubleshooting of latencies and hot partitions.
• Experience with at least one major Cassandra migration or upgrade, preferably involving schema changes.
• Good knowledge of Linux and bare-metal infrastructure.
• Experience in technically leading a team and presenting architectural decisions to both technical and business stakeholders.
• Excellent command of Italian, written and spoken: the role involves daily interaction with the client and writing technical documentation in Italian. Nice to have
• Experience with Cassandra 4.x/5.0 (SAI, BTI, UCS) or ScyllaDB.
• Apache Spark and Spark Cassandra Connector for large-scale data movement.
• Messaging systems: NATS/JetStream, Kafka or similar.
• Knowledge of Cassandra drivers in Node.js or Java. Work mode: Full remote | Start: ASAP | Duration: 1 year Recruitment Process Our selection process is streamlined into 2 stages:
• Discovery Call: Short initial interview with our HR team.
• Technical & Fit Interview: In-depth discussion with our Delivery Team Leaders / Management.

How to Apply
You can apply directly via LinkedIn or send your CV to [email protected].

📌 Senior Data Architect Freelance (Italia)
🏢 Bitrock
📍 Italia