diff --git a/changes/3174.fix.md b/changes/3174.fix.md
new file mode 100644
index 0000000000..c043ecb8c6
--- /dev/null
+++ b/changes/3174.fix.md
@@ -0,0 +1 @@
+Fix service not started when `[logging].rotation-size` config is set
diff --git a/src/ai/backend/logging/types.py b/src/ai/backend/logging/types.py
index 57ad25ab23..44a37e1578 100644
--- a/src/ai/backend/logging/types.py
+++ b/src/ai/backend/logging/types.py
@@ -124,8 +124,10 @@ class SimpleBinarySizeTrafaret(t.Trafaret):
     }
     endings = ("ibytes", "ibyte", "ib", "bytes", "byte", "b")
 
-    def check_and_return(self, value: str) -> int:
+    def check_and_return(self, value: str | int) -> int:
         orig_value = value
+        if isinstance(value, int):
+            return value
         value = value.strip().replace("_", "")
         try:
             return int(value)