No Local Storage Cache – Due to Autoscaling

If Local Storage Cache is not used due to autoscaling needs on Azure (since local storage is tied to a single instance), you should consider distributed caching solutions. These solutions provide caching that is accessible across multiple instances, ensuring consistent and scalable performance in an autoscaled environment. Here are the top alternatives to Local Storage Cache in such cases:

1. Azure Redis Cache

Azure Redis Cache is a managed, high-performance distributed caching service that can be accessed by multiple instances. It is ideal for autoscaling environments because all instances share the same cache, and it supports:

• Object Caching: Store frequently accessed database results or API responses, which helps reduce load on the database and backend.
• Page and Fragment Caching: Redis can cache entire pages or specific page fragments, which is useful for complex, database-driven pages created by plugins like Elementor.
• Session State Caching: Store user sessions in Redis, making it possible for users to retain their session data as they’re routed across instances.

Pros:

• Highly scalable, resilient, and suitable for high-traffic sites.
• Redis supports various caching structures, such as lists, hashes, and sorted sets, allowing for flexible caching strategies.

Cons:

• Requires integration with a Redis-compatible WordPress plugin, such as Redis Object Cache.
• Redis incurs additional costs, though it’s often cost-effective for large, autoscaling environments.

2. Azure Blob Storage + CDN

Using Azure Blob Storage combined with Azure Content Delivery Network (CDN) can help manage static assets efficiently across autoscaled instances:

• Blob Storage: Offload WordPress media files (images, videos, CSS, and JavaScript) to Azure Blob Storage. This keeps your instance storage requirements low and ensures that autoscaled instances aren’t duplicating large files.
• Azure CDN: By serving Blob Storage files through the CDN, users can access static content from geographically closer locations, improving load times and reducing server load.

Pros:

• Great for distributing large, media-heavy files and minimizing storage redundancy across instances.
• Reduces latency for users across different regions.

Cons:

• Only beneficial for static files and media, not dynamic content (such as HTML output of pages).

3. Application-Level Caching Plugins with Distributed Storage

Several caching plugins can be configured to work with distributed storage. W3 Total Cache and WP Super Cache can be configured to use Azure Redis or a CDN for cache storage, ensuring that cached content remains consistent across instances. These plugins support:

• Fragment Caching: Useful for caching portions of a page, allowing selective updates without regenerating the entire page.
• Database Caching: Caches the results of database queries, reducing the load on the database in an autoscaled environment.
• Page Caching (with CDN): Enables complete page caching on a CDN, reducing server-side load.

Pros:

• Easy to configure and integrates well with autoscaling.
• Offers multiple caching methods, allowing for more control over what is cached and where it is stored.

Cons:

• Some caching plugins may not fully support distributed caching without specific configurations.

4. Azure Front Door

Azure Front Door can act as both a global load balancer and a CDN. It caches content closer to the end users and directs traffic to the nearest backend instance based on availability and load.

• Static Content Caching: Caches static content, such as CSS, JavaScript, and images, at the edge for faster delivery.
• Dynamic Site Acceleration: Uses optimization techniques to speed up delivery of non-cacheable content, which is useful for dynamic, frequently-changing content.

Pros:

• Seamlessly integrates with Azure services and provides intelligent traffic management.
• Ideal for global applications needing high availability, fast response times, and efficient autoscaling.

Cons:

• Mostly suitable for caching static assets; dynamic content caching might require additional configuration.

Summary

In an autoscaled environment on Azure without Local Storage Cache, Azure Redis Cache for database and session caching combined with Azure Blob Storage + CDN for static assets is often the best approach. These solutions provide a scalable, shared caching layer that reduces load and improves performance without dependency on a single instance’s local storage.