Frequent azure redis cache timeout in azure web app

Question

We are using azure redis cache and in web app , but we are facing frequent time out issue - Timeout performing EVAL, inst: 1, queue: 2, qu: 0, qs: 2, qc: 0, wr: 0, wq: 0, in: 0, ar: 0, clientName: LPC-2VDKZH3, serverEndpoint: Unspecified/dv-uks-productmasterv2-rc-01.redis.cache.windows.net:6380, keyHashSlot: 1726 (Please take a look at this article for some common client-side issues that can cause timeouts: http://stackexchange.github.io/StackExchange.Redis/Timeouts)"http://stackexchange.github.io/stackexchange.redis/timeouts)")

Any help on this please?

Answer 1

Hi @Aparna Manoharan,

Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.

We would like to inform you that, to resolve frequent Azure Redis Cache timeouts in an Azure Web App, you should first monitor your cache usage to identify the source of the issue, such as high memory usage, network bandwidth limitations, or a poorly configured client, then adjust your cache size, optimize your cache access patterns, review network connectivity, and ensure proper client settings like timeouts and connection pooling; if necessary, scale your cache tier to a larger size with more resources.

Key steps to troubleshoot and resolve Azure Redis Cache timeouts:

1. Monitor and Analyze:

• Check Azure Portal Metrics: Access the Azure portal to view metrics like cache hits/misses, memory usage, CPU utilization, network throughput, and connected clients on your Redis cache to identify potential bottlenecks.
• Review Application Logs: Analyze your web app logs for specific error messages related to Redis timeouts to pinpoint the problem area.

2. Client-Side Optimization:

• Connection Pooling: Use connection pooling in your client library to reuse connections and avoid overhead of establishing new connections for each request.
• Timeout Settings: Adjust the timeout values in your client configuration to handle potential network delays.
• Efficient Cache Access: Design your cache access patterns to minimize unnecessary cache operations and large data sizes.
• Key Expiration: Set appropriate expiration times for cached data to prevent stale data from accumulating.

3. Cache Configuration:

• Scale Cache Size: If your cache is experiencing high memory usage, consider scaling up to a larger cache tier with more memory and network capacity.
• Cache Tier Selection: Choose the appropriate cache tier based on your workload requirements (Basic for simple use cases, Premium for high throughput and clustering).
• Region Placement: Ensure your Redis cache is located in the same Azure region as your web app to minimize network latency.

4. Network Considerations:

• Network Bandwidth: Check if your network has sufficient bandwidth to handle the data transfer between your web app and the cache.
• Virtual Network Configuration: Verify that your web app and Redis cache are properly configured within the same virtual network.

5. Other Potential Issues:

• Redis Updates: Be aware of potential downtime during Redis service updates and patching.
• Client Code Issues: Review your application code to ensure proper handling of Redis exceptions and retries.

Please refer to the below mentioned links for more information.

https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-troubleshoot-timeouts

https://azure.microsoft.com/en-us/blog/investigating-timeout-exceptions-in-stackexchange-redis-for-azure-redis-cache/#:~:text=Check%20if%20you%20your%20Azure,synctimeout%20to%20a%20higher%20value.

https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-monitor-troubleshoot-faq

https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-troubleshoot-connectivity

I hope, This response will address your query and helped you to overcome on your challenges.

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