Suggestions for Optimizing Redis Memory Settings

[Mohammed Ismail]

Dear OpenWisp Community,

I hope this message finds you well.

I have been exploring ways to optimize the memory usage of Redis in our OpenWisp deployments. After seeking advice, it was suggested to me that adjusting the `maxmemory-policy` and `maxmemory` settings could help improve performance and stability.

### Suggested Settings

1. **Maxmemory Policy:**
   It was recommended to set the `maxmemory-policy` to `allkeys-lru`. This policy helps manage memory usage by evicting the least recently used (LRU) keys when the memory limit is reached.

   **Configuration:**
   ```plaintext
   maxmemory-policy allkeys-lru
   ```

2. **Maxmemory Size:**
   As for the `maxmemory` setting, it was suggested to configure it based on a percentage of the available RAM on the server. Allocating around 75% of the total RAM for Redis could be a good starting point, while leaving the remaining 25% for other processes and the operating system.

   **Configuration:**
   ```plaintext
   maxmemory <calculated value>
   ```

### Steps to Update Configuration

1. **Edit the Redis Configuration File:**
   Open the Redis configuration file (`/etc/redis/redis.conf`) in a text editor:
   ```bash
   sudo nano /etc/redis/redis.conf
   ```

2. **Update `maxmemory` and `maxmemory-policy`:**
   Add or update the following lines as per your server's RAM percentage allocation:
   ```plaintext
   maxmemory <calculated value>
   maxmemory-policy allkeys-lru
   ```

3. **Save and Exit:**
   Save the changes and exit the text editor. For `nano`, press `Ctrl+X`, then `Y`, and then `Enter`.

4. **Restart Redis Server:**
   Restart the Redis service to apply the changes:
   ```bash
   sudo systemctl restart redis-server
   ```

I hope these suggestions are helpful. If anyone has further insights or alternative recommendations, I would greatly appreciate your input.

Best regards, And thanks ChatGPT 😁

Muhammad