etcdserver:FDUsage set ticker to 10 minute from 5 seconds. This ticke…

…r will check File Descriptor Requirements ,and count all fds in used. And recorded some logs when in used >= limit/5*4. Just recorded message. If fds was more than 10K,It's low performance due to FDUsage() works. So need to increase it.

see #11969 for more detail.

etcdserver/metrics.go

@@ -184,7 +184,13 @@ func init() {
 }
 
 func monitorFileDescriptor(lg *zap.Logger, done <-chan struct{}) {
-	ticker := time.NewTicker(5 * time.Second)
+
+	// This ticker will check File Descriptor Requirements ,and count all fds in used.
+	// And recorded some logs when in used >= limit/5*4. Just recorded message.
+	// If fds was more than 10K,It's low performance due to FDUsage() works.
+	// So need to increase it.
+	// See https://github.com/etcd-io/etcd/issues/11969 for more detail.
+	ticker := time.NewTicker(10 * time.Minute)
 	defer ticker.Stop()
 	for {
 		used, err := runtime.FDUsage()