Why caching improves performance in Azure - Why It Works

Introduction

Caching stores copies of data in a fast storage area so that future requests for that data can be served quickly. This reduces the time it takes to get data and lowers the load on the main data source.

When your web app needs to show the same data to many users quickly without asking the database every time

When you want to reduce the cost and delay of repeatedly fetching data from a slow or expensive service

When you want to improve user experience by making pages or features load faster

When you want to handle more users at once without slowing down your system

When you want to avoid repeated calculations by storing results temporarily

Config File - azure-cache-config.json

azure-cache-config.json

{
  "name": "myCache",
  "location": "eastus",
  "sku": {
    "name": "Standard",
    "family": "C",
    "capacity": 1
  },
  "enableNonSslPort": false,
  "redisConfiguration": {
    "maxmemory-policy": "allkeys-lru"
  }
}

This JSON configures an Azure Cache for Redis instance named myCache in the East US region.

The sku section sets the cache size and type.

enableNonSslPort is false to enforce secure connections.

The redisConfiguration sets the eviction policy to remove least recently used keys when memory is full.

Commands

This command creates an Azure Redis Cache instance named 'myCache' in the 'eastus' region under the resource group 'myResourceGroup'. It uses the Standard SKU with a small VM size and disables the non-SSL port for security.

Terminal

az redis create --name myCache --resource-group myResourceGroup --location eastus --sku Standard --vm-size C1 --enable-non-ssl-port false

Expected Output

{

  "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/myResourceGroup/providers/Microsoft.Cache/Redis/myCache",

  "location": "eastus",

  "name": "myCache",

  "properties": {

    "provisioningState": "Succeeded",

    "hostName": "myCache.redis.cache.windows.net",

    "port": 6379,

    "sslPort": 6380

  },

  "sku": {

    "name": "Standard",

    "family": "C",

    "capacity": 1

  },

  "type": "Microsoft.Cache/Redis"

}

→

--sku - Sets the cache type and size

→

--enable-non-ssl-port - Disables insecure connections

This command retrieves details about the Redis Cache instance to verify it was created successfully and check its settings.

Terminal

az redis show --name myCache --resource-group myResourceGroup

Expected Output

{

  "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/myResourceGroup/providers/Microsoft.Cache/Redis/myCache",

  "location": "eastus",

  "name": "myCache",

  "properties": {

    "provisioningState": "Succeeded",

    "hostName": "myCache.redis.cache.windows.net",

    "port": 6379,

    "sslPort": 6380

  },

  "sku": {

    "name": "Standard",

    "family": "C",

    "capacity": 1

  },

  "type": "Microsoft.Cache/Redis"

}

This command sets a maintenance window on Monday at 2 AM for 60 minutes to apply updates without unexpected downtime.

Terminal

az redis patch-schedule create --name myCache --resource-group myResourceGroup --day-of-week Monday --start-hour 2 --maintenance-window 60

Expected Output

{

  "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/myResourceGroup/providers/Microsoft.Cache/Redis/myCache/patchSchedules/Default",

  "dayOfWeek": "Monday",

  "startHourUtc": 2,

  "maintenanceWindow": 60

}

→

--day-of-week - Specifies the day for maintenance

→

--start-hour - Specifies the hour to start maintenance

Key Concept

If you remember nothing else from this pattern, remember: caching stores data closer to where it is needed to make access much faster and reduce load on slower sources.

Common Mistakes

Not disabling the non-SSL port when creating the cache

This allows insecure connections that can expose data to attackers

Always set --enable-non-ssl-port false to enforce secure connections

Not verifying the cache creation with az redis show

You might think the cache is ready when it is still provisioning or failed

Run az redis show to confirm the cache is provisioned and ready

Not setting a maintenance window

Updates can happen at unexpected times causing downtime

Use az redis patch-schedule create to set a predictable maintenance time

Summary

Create an Azure Redis Cache instance with secure settings using az redis create.

Verify the cache is ready with az redis show before using it.

Set a maintenance window to control when updates happen and avoid surprises.