Caching Strategies for MediaWiki
- Caching Strategies for MediaWiki
This article details various caching strategies for improving the performance of your MediaWiki installation. Effective caching is crucial for handling high traffic and providing a responsive user experience. This guide is geared towards system administrators and those responsible for maintaining a MediaWiki server.
Understanding Caching in MediaWiki
MediaWiki, by default, dynamically generates pages with each request. This can become a significant performance bottleneck as the wiki grows. Caching aims to store frequently accessed data, reducing the load on the database and PHP interpreter. Various levels of caching exist, each with its own benefits and complexities. We'll cover several key strategies here. Remember to always test changes in a staging environment before applying them to production. See Manual:Configuration changes for details on safe configuration changes.
Database Query Caching
The database is often the slowest component of a MediaWiki installation. Caching frequently executed queries can dramatically improve performance.
Memcached
Memcached is a high-performance, distributed memory object caching system. Integrating Memcached with MediaWiki is highly recommended.
| Configuration Parameter | Description | Default Value |
|---|---|---|
| `$wgMemCachedLocalServers` | An array of Memcached server addresses. Format: `array('127.0.0.1:11211');` | `'127.0.0.1:11211'` |
| `$wgMemCacheTTL` | The time-to-live (TTL) for cached data, in seconds. | `3600` (1 hour) |
| `$wgUseMemCached` | Enables or disables Memcached integration. Set to `true` to enable. | `false` |
To enable Memcached, you'll need to install the Memcached daemon on your server and the PHP Memcached extension. See Manual:Configuration settings for more details. Ensure the web server user has permissions to connect to the Memcached server.
Advanced Database Caching
Beyond Memcached, consider optimizing database queries themselves. Indexing frequently queried columns is essential. Use `EXPLAIN` statements in MySQL to analyze query performance and identify potential bottlenecks. See the Database page for more information.
Object Caching
Object caching stores the result of PHP operations, such as parsing templates or fetching data from the database.
APCu
APCu (Alternative PHP Cache User) is a PHP extension that provides in-memory data storage. It's a good alternative to Memcached, especially on servers where Memcached isn't feasible.
| Configuration Parameter | Description | Default Value |
|---|---|---|
| `$wgAPCPageCache` | Enables or disables APCu page caching. Set to `true` to enable. | `false` |
| `$wgAPCPathInfoCache` | Enables or disables APCu path info caching. | `false` |
| `$wgAPCTTL` | The time-to-live (TTL) for cached data, in seconds. | `3600` (1 hour) |
Ensure the APCu extension is installed and enabled in your PHP configuration. See Manual:APCu for setup instructions.
Other Object Caches
Other options include Xcache and WinCache, but these are less actively maintained than APCu and Memcached. Consider their maturity and support before deploying them.
Page Caching
Page caching stores the fully rendered HTML output of pages. This is the most aggressive form of caching, providing the fastest response times.
Squid
Squid is a popular proxy server and web cache. It can cache static and dynamic content, including MediaWiki pages.
| Configuration Parameter (Squid) | Description | Example Value |
|---|---|---|
| `cache_mem` | The amount of memory Squid uses for caching. | `256 MB` |
| `cache_dir` | The directory where Squid stores cached data on disk. | `/var/spool/squid` |
| `access_log` | The path to the access log file. | `/var/log/squid/access.log` |
Configuring Squid requires a good understanding of its configuration file. Properly configuring cache hierarchies and access control lists is crucial for optimal performance and security. See Squid for more information. Ensure Squid is configured to respect MediaWiki's cache control headers.
Varnish
Varnish is another high-performance HTTP accelerator and reverse proxy. It's designed specifically for caching HTTP content. Varnish often outperforms Squid for dynamic content. See Varnish for more information.
Important Considerations
- **Cache Invalidation:** When content is updated, the cache must be invalidated to ensure users see the latest version. MediaWiki has mechanisms for automatic cache invalidation, but it's essential to understand how they work.
- **Cache Size:** Properly sizing your cache is crucial. Too small, and you won't see significant performance gains. Too large, and you'll waste memory.
- **Monitoring:** Regularly monitor your cache hit rate and adjust your configuration accordingly.
- **Testing:** Always test your caching configuration thoroughly before deploying it to a production environment. Use tools like `ab` (ApacheBench) or `siege` to simulate load. See Benchmarking.
- **Purge Cache:** Utilize the `action=purge` parameter on pages to manually refresh the cache when needed. See Help:Purge.
- **CDN (Content Delivery Network):** Consider using a CDN to cache static assets (images, CSS, JavaScript) closer to your users. See Content Delivery Network.
Further Reading
- Manual:Caching - Official MediaWiki documentation on caching.
- Manual:Configuration settings - Detailed information on configuration parameters.
- Performance - General information on optimizing MediaWiki performance.
- Database - Information on database optimization.
Intel-Based Server Configurations
| Configuration | Specifications | Benchmark |
|---|---|---|
| Core i7-6700K/7700 Server | 64 GB DDR4, NVMe SSD 2 x 512 GB | CPU Benchmark: 8046 |
| Core i7-8700 Server | 64 GB DDR4, NVMe SSD 2x1 TB | CPU Benchmark: 13124 |
| Core i9-9900K Server | 128 GB DDR4, NVMe SSD 2 x 1 TB | CPU Benchmark: 49969 |
| Core i9-13900 Server (64GB) | 64 GB RAM, 2x2 TB NVMe SSD | |
| Core i9-13900 Server (128GB) | 128 GB RAM, 2x2 TB NVMe SSD | |
| Core i5-13500 Server (64GB) | 64 GB RAM, 2x500 GB NVMe SSD | |
| Core i5-13500 Server (128GB) | 128 GB RAM, 2x500 GB NVMe SSD | |
| Core i5-13500 Workstation | 64 GB DDR5 RAM, 2 NVMe SSD, NVIDIA RTX 4000 |
AMD-Based Server Configurations
| Configuration | Specifications | Benchmark |
|---|---|---|
| Ryzen 5 3600 Server | 64 GB RAM, 2x480 GB NVMe | CPU Benchmark: 17849 |
| Ryzen 7 7700 Server | 64 GB DDR5 RAM, 2x1 TB NVMe | CPU Benchmark: 35224 |
| Ryzen 9 5950X Server | 128 GB RAM, 2x4 TB NVMe | CPU Benchmark: 46045 |
| Ryzen 9 7950X Server | 128 GB DDR5 ECC, 2x2 TB NVMe | CPU Benchmark: 63561 |
| EPYC 7502P Server (128GB/1TB) | 128 GB RAM, 1 TB NVMe | CPU Benchmark: 48021 |
| EPYC 7502P Server (128GB/2TB) | 128 GB RAM, 2 TB NVMe | CPU Benchmark: 48021 |
| EPYC 7502P Server (128GB/4TB) | 128 GB RAM, 2x2 TB NVMe | CPU Benchmark: 48021 |
| EPYC 7502P Server (256GB/1TB) | 256 GB RAM, 1 TB NVMe | CPU Benchmark: 48021 |
| EPYC 7502P Server (256GB/4TB) | 256 GB RAM, 2x2 TB NVMe | CPU Benchmark: 48021 |
| EPYC 9454P Server | 256 GB RAM, 2x2 TB NVMe |
Order Your Dedicated Server
Configure and order your ideal server configuration
Need Assistance?
- Telegram: @powervps Servers at a discounted price
⚠️ *Note: All benchmark scores are approximate and may vary based on configuration. Server availability subject to stock.* ⚠️