diff --git a/src/dnslib/utils.c b/src/dnslib/utils.c
index b7e28d1d476658e676aeb7d19ca38ced1151fa51..e407a7d5fe9111bf29cf5ea3aa4730592ec63b8e 100644
--- a/src/dnslib/utils.c
+++ b/src/dnslib/utils.c
@@ -62,3 +62,9 @@ size_t dnslib_strlcpy(char *dst, const char *src, size_t size)
 
 	return(s - src - 1);        /* count does not include NUL */
 }
+
+unsigned dnslib_lcg_rand()
+{
+	static unsigned x = time(0);
+	return x = 1664525 * x + 1013904223;
+}
diff --git a/src/dnslib/utils.h b/src/dnslib/utils.h
index 2b3b57100ff8433cb8e8a4654484b8b881cf75c0..34524f00f2498b9a7bc7dbbe866b6100179e0bcf 100644
--- a/src/dnslib/utils.h
+++ b/src/dnslib/utils.h
@@ -133,6 +133,15 @@ static inline void dnslib_wire_write_u32(uint8_t *pos, uint32_t data)
 	pos[3] = (uint8_t)(data & 0xff);
 }
 
+/*!
+ * \brief Linear congruential generator.
+ *
+ * Simple pseudorandom generator for general purpose.
+ * \warning Do not use for cryptography.
+ * \return Random number <0, UINT_MAX>
+ */
+unsigned dnslib_lcg_rand();
+
 #endif /* _KNOT_DNSLIB_UTILS_H_ */
 
 /*! @} */
diff --git a/src/knot/server/dthreads.c b/src/knot/server/dthreads.c
index a6ae6749666a5e41eba2d6ca97ab6e485b75b51b..336cec62df74b3d705429480f0964bc053cf1e59 100644
--- a/src/knot/server/dthreads.c
+++ b/src/knot/server/dthreads.c
@@ -596,9 +596,7 @@ int dt_start(dt_unit_t *unit)
 		dthread_t *thread = unit->threads[i];
 		int res = dt_start_id(thread);
 		if (res != 0) {
-			log_server_error("dthreads: Failed to "
-			                 "create thread '%d'.",
-			                 i);
+			debug_dt("dthreads: Failed to create thread '%d'.", i);
 			dt_unit_unlock(unit);
 			pthread_mutex_unlock(&unit->_notify_mx);
 			return res;
@@ -943,7 +941,7 @@ int dt_optimal_size()
 		return ret + CPU_ESTIMATE_MAGIC;
 	}
 #endif
-	log_server_info("dthreads: Failed to fetch the number of online CPUs.");
+	debug_dt("dthreads: Failed to fetch the number of online CPUs.");
 	return DEFAULT_THR_COUNT;
 }