diff --git a/nixos/modules/system/boot/systemd.nix b/nixos/modules/system/boot/systemd.nix
index f955746f78a0..2167df60bc9a 100644
--- a/nixos/modules/system/boot/systemd.nix
+++ b/nixos/modules/system/boot/systemd.nix
@@ -593,6 +593,9 @@ in
each other's limit. The value may be specified in the following
units: s, min, h, ms, us. To turn off any kind of rate limiting,
set either value to 0.
+
+ See for important
+ considerations when setting this value.
'';
};
@@ -604,6 +607,19 @@ in
interval) that is applied to all messages generated on the system.
This rate limiting is applied per-service, so that two services
which log do not interfere with each other's limit.
+
+ Note that the effective rate limit is multiplied by a factor derived
+ from the available free disk space for the journal as described on
+
+ journald.conf(5).
+
+ Note that the total amount of logs stored is limited by journald settings
+ such as SystemMaxUse, which defaults to a 4 GB cap.
+
+ It is thus recommended to compute what period of time that you will be
+ able to store logs for when an application logs at full burst rate.
+ With default settings for log lines that are 100 Bytes long, this can
+ amount to just a few hours.
'';
};