Proxy settings reference
This page is a reference for the settings you can optionally define to fine-tune the behavior of the Memcached built-in proxy. For a guide to applying these settings, see Adjust proxy settings.
active_req_limit
| Type | integer |
|---|---|
| Default | 0 |
The proxy returns a fast fail on any request if it it already actively processing more than this many requests.
If set to 0, then the proxy does not impose this limit.
backend_connect_timeout
| Type | float |
|---|---|
| Default | 5 |
The time, in fractional seconds, before an attempted connection between the proxy and a backend times out.
backend_failure_limit
| Type | integer |
|---|---|
| Default | 3 |
The number of consecutive connection or validation failures that the proxy tolerates from a backend before the proxy marks the backend as bad.
backend_flap_backoff_max
| Type | integer |
|---|---|
| Default | 3600 |
Maximum number of whole seconds to wait before retrying a flapping server. Ensures servers with ephemeral issues are occasionally brought back in a reasonable timeframe.
backend_flap_backoff_ramp
| Type | float |
|---|---|
| Default | 1.5 |
The proxy uses this fractional second value to determine a backoff for how often to retry unhealthy backends. The proxy derives the backoff time by multiplying the following numbers:
- The value of
backend_flap_backoff_ramp - The value of
backend_retry_waittime - The number of times the backend in question has flapped
backend_flap_time
| Type | integer |
|---|---|
| Default | 0 |
The number of seconds a that backend must be held open without errors, or else it is considered to be flapping.
If set to 0, then the proxy never marks a backend as flapping.
backend_read_timeout
| Type | integer |
|---|---|
| Default | 3 |
The time, in fractional seconds, that the proxy waits for a response from a connected backend after forwarding a client command to it.
backend_retry_waittime
| Type | integer |
|---|---|
| Default | 3 |
The time, in whole seconds, that the proxy waits before retrying a failed connection with a backend.
backend_use_iothread
| Type | boolean |
|---|---|
| Default | false |
Whether or not a backend is hanndled by worker threads or a dedicated I/O thread, by default.
The default value of false provides better scalability at the cost of more TCP connections and less batching of backend syscalls.
buffer_memory_limit
| Type | integer |
|---|---|
| Default | 0 |
The proxy returns a fast fail on any request if more than roughly this many kilobytes are actively in use by requests for request or response value buffers.
If set to 0, then the proxy does not impose this limit.
tcp_keepalive
| Type | boolean |
|---|---|
| Default | false |
Whether or not all new backends use TCP keepalive.