The error 'memcached failed to set key' occurs when Memcached is unable to store a new value for a specific key. There could be multiple reasons behind this issue, including insufficient memory allocated for Memcached, a communication failure between the client and the server, or an attempt to store a value that exceeds the maximum allowed size. Another possible cause for this error could be a configuration issue where the server has reached its maximum connection limit.
Solution - Here's How To Resolve It
To resolve this issue, you can try several solutions:
Increase the memory allocated for Memcached by modifying the memcached.conf file. You can increase the cache size to accommodate larger values.
Check if there is any communication failure between the client and server. Ensure that the client and server are running on the same network and that there are no firewall restrictions that may prevent communication.
Reduce the size of the value being stored. The maximum size allowed by Memcached is 1MB, so make sure the value you're trying to store doesn't exceed this limit.
If your server has reached its maximum connection limit, consider using a load balancer to distribute connections across multiple servers. Alternatively, you can modify Memcached's configuration to increase the number of connections it can handle.
Finally, check for any other errors in your code or application that may be causing the issue.