fix(api): change speedtest interval to every 4 hrs

this is necessary, because users on a metered connection have noticed high network usage.
Every four hours should still be enough to get a basic view on what is happening.

Also there is a new warning on the install page to warn about this risk.

fixes #253

apps/api/src/config.ts

@@ -64,7 +64,7 @@ export const CONFIG: Config = {
   ram_shown_datapoints: numNull(penv('RAM_SHOWN_DATAPOINTS')) ?? 20,
   ram_poll_interval: numNull(penv('RAM_POLL_INTERVAL')) ?? 1000,
 
-  speed_test_interval: numNull(penv('SPEED_TEST_INTERVAL')) ?? 60,
+  speed_test_interval: numNull(penv('SPEED_TEST_INTERVAL')) ?? 60 * 4,
   network_widget_grow: numNull(penv('NETWORK_WIDGET_GROW')) ?? 6,
   network_widget_min_width: numNull(penv('NETWORK_WIDGET_MIN_WIDTH')) ?? 500,
   network_shown_datapoints: numNull(penv('NETWORK_SHOWN_DATAPOINTS')) ?? 20,

apps/docs/docs/config/widget-options/network.md

@@ -12,7 +12,7 @@ tags:
 At which interval the network speed-test should be rerun (in minutes).
 
 - type: `number`
-- default: `60`
+- default: `240` (every 4 hours)
 
 ## `DASHDOT_NETWORK_WIDGET_GROW`
 

apps/docs/docs/install/index.md

@@ -29,6 +29,16 @@ docker container run -it \
 
 :::
 
+:::warning
+
+The speed testing feature can consume significant amounts of bandwidth, which can pose
+problems if your usage is metered (say, by a VPS provider).
+
+Setting the environment variable [`DASHDOT_SPEED_TEST_INTERVAL`](./config/widget-options/network#dashdot_speed_test_interval)
+to a higher number can mitigate this concern.
+
+:::
+
 ## Installation Options
 
 ```mdx-code-block