Comparing Persistence: Redis vs NCache
Data persistence is critical in ensuring high availability, disaster recovery, and durability in distributed caching. Both Redis and NCache offer options for this process, but their implementations differ significantly. This blog explores why it is essential, compares the mechanisms on offer, and highlights why NCache provides a more comprehensive solution for modern applications.
Why Persistence Matters in a Distributed Cache
Caching is inherently volatile, but this mechanism ensures that cache data remains available regardless of system failures, restarts, or crashes. This is particularly valuable in scenarios where:
- Applications experience unexpected crashes or restarts.
- Infrastructure failures like power outages or cloud disruptions occur.
- Costly database operations need to be reduced by maintaining cached data.
- Scalability and disaster recovery require quick cache restoration.
By leveraging this mechanism, distributed caches can reduce risks of data loss and improve recovery times, ensuring consistent performance and availability.
Overview of Redis Persistence
Redis offers multiple such mechanisms, each with its own pros and cons.
Redis Persistence Options
Redis offers users the following options for persisting their cache data.
- RDB (Redis Database): Takes periodic snapshots of data at defined intervals, offering durability but with a risk of data loss if the server crashes between snapshots.
- AOF (Append-Only File): Logs every write operation, allowing full data recovery at the cost of increased storage consumption.
- Hybrid Mode (AOF + RDB): Combines both methods to optimize durability while minimizing storage impact.
Limitations of Redis Persistence
However, there are significant disadvantages to this approach.
- Data Loss in RDB due to Long Backup Intervals: Since RDB takes periodic snapshots, any data changes between snapshots are lost if the server crashes before the next scheduled backup. This creates a risk of inconsistency, especially in high-transaction environments.
- Excessive Memory Consumption: AOF consumes a lot of memory particularly in write-heavy applications.
- No Automatic Recovery from RDB and AOF: Recovery from RDB and AOF requires manual intervention, leading to increased downtime. This process involves manually restoring data, which can be time-consuming, especially for large datasets.
- Partially Integrated: Redis clusters do not offer complete persistence integrations leading to operational complexities when scaling.
Why Choose NCache Live Persistence?
NCache delivers an advanced live persistence mechanism designed for high performance, scalability, and real-time durability. It ensures near real-time data consistency with minimal performance impact while offering seamless scalability and monitoring.
Key Benefits
Users employing NCache's persistent data store benefit from the following:
- Client Cache (InProc Speed): Boosts performance by reducing round trips to the distributed cache with an in-process caching option.
- Asynchronous Persistence: Writes to the data store occur in the background, ensuring minimal impact on application performance.
- Bucket-Level Persistence: Divides the cache into 100 buckets, optimizing data distribution, storage utilization, and seamless scalability.
- Automatic Data Loading: Ensures continuous availability by automatically loading data from the persistent store during cache startup, node joins, and node leaves.
- Data Recovery on Restart: Restores cached data instantly upon service restart for uninterrupted operations.
- Automatic Data Rebalancing: Evenly redistributes data across nodes when they are added or removed, maintaining efficiency and availability.
- Async Queue Replication: Replicates write queues on replica nodes in Partition-Replica Cache topology to prevent data loss in case of primary node failure.
- Powerful Monitoring: Provides real-time insights with performance counters and a dashboard-style NCache Monitor for tracking operations.
How to Configure NCache Persistence?
Follow the steps below to utilize the NCache persistent data store after you have downloaded and installed NCache on each node.
- Create a clustered cache, i.e., a Distributed Cache with Persistence with the NCache Management Center or PowerShell.
- As part of the creation process specify the store location as detailed in the NCache Administrators Guide.
Alternatively, if users have already created a cache and connected it to their application they can set a persistence interval, a persistent store and enable it.
Conclusion
Distributed caching persistence is essential for ensuring data reliability, availability, and disaster recovery. While Redis provides various options, NCache excels with near real-time persistence, efficient asynchronous writes, dynamic scalability, and robust monitoring tools. For enterprises seeking a high-performance, scalable, and highly available data store, NCache is the ideal choice. Experience seamless distributed caching with NCache today!