Memcached Tuning Parameters
Memcached is a high-performance memory caching system, with its primary goal of improving application performance and efficiency.
Memory Usage
1. Memory Usage Ratio
Memcached recommends keeping the memory usage ratio between 10% and 20%. A ratio that is too low may prevent Memcached from effectively caching data, while a ratio that is too high can lead to system resource exhaustion.
2. Page Size
Memcached recommends a page size of 16MB or 32MB per page. This page size can be adjusted based on actual needs, but generally, 16MB or 32MB are good choices.
3. Memory Eviction Policy
Memcached provides various memory eviction policies that can be adjusted according to needs. For example:
- LRU (Least Recently Used): Removes the least frequently used data from the cache.
- LRUMove: Moves the least frequently used data to a separate area and removes it after a period of time.
4. Memory Reservation
Memcached recommends reserving a certain amount of memory for the system to avoid memory exhaustion caused by a full cache. This value can be adjusted based on actual conditions, but generally, 10% to 20% of total memory is a suitable reservation range.
Maximum Connections
1. Connection Limit
Memcached recommends keeping the maximum connections (max connections) at a relatively low number. Too many connections can cause system performance degradation, while too few can limit application concurrency.
2. Client Connections
Memcached recommends a client connection count between 1000 and 5000. This range can be adjusted based on actual needs, but generally, 500 to 2000 is a better connection count range.
3. Port and Network Configuration
Memcached's maximum connection count is also affected by network and port settings. For systems with high performance requirements, consider using multiple Memcached instances and increasing the connection count.
4. Network Optimization Strategies
Memcached provides various network optimization strategies, such as:
- Slow Link Detection: Identifies and handles slow links.
- Data Replication and Transfer: Uses efficient data replication and transfer strategies to reduce network latency.
5. Monitoring and Fault Detection
Memcached provides various monitoring and fault detection tools that can help system administrators regularly check Memcached instances and perform necessary maintenance.
Summary
Memcached tuning parameters are designed to ensure applications run faster and more stably. By adjusting these parameters, system administrators can improve Memcached performance, reduce failure rates, and lower costs. Achieve the best results by adjusting these parameters according to actual needs.