diff --git a/server.c b/server.c
index 081c1e9..ae0e823 100644
--- a/server.c
+++ b/server.c
@@ -77,7 +77,6 @@ server_new(const char *cfg_file) {
 	struct server *s = calloc(1, sizeof(struct server));
 
 	s->cfg = conf_read(cfg_file);
-	pthread_spin_init(&s->log_lock, PTHREAD_PROCESS_SHARED);
 
 	/* workers */
 	s->w = calloc(s->cfg->http_threads, sizeof(struct worker*));
@@ -155,6 +154,8 @@ server_start(struct server *s) {
 	signal(SIGPIPE, SIG_IGN);
 #endif
 
+	slog_init(s);
+
 	/* start worker threads */
 	for(i = 0; i < s->cfg->http_threads; ++i) {
 		worker_start(s->w[i]);
diff --git a/server.h b/server.h
index 4c85e64..42438b3 100644
--- a/server.h
+++ b/server.h
@@ -21,7 +21,10 @@ struct server {
 	int next_worker;
 
 	/* log lock */
-	pthread_spinlock_t log_lock;
+	struct {
+		pid_t self;
+		int fd;
+	} log;
 };
 
 struct server *
diff --git a/slog.c b/slog.c
index 5722b35..73a68d3 100644
--- a/slog.c
+++ b/slog.c
@@ -5,42 +5,63 @@
 #include <time.h>
 #include <sys/types.h>
 #include <unistd.h>
-#include <pthread.h>
 #include <string.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 #include "slog.h"
 #include "server.h"
 #include "conf.h"
 
+/**
+ * Initialize log writer.
+ */
+void
+slog_init(struct server *s) {
+
+	s->log.self = getpid();
+
+	if(s->cfg->logfile) {
+		s->log.fd = open(s->cfg->logfile,
+			O_WRONLY | O_APPEND | O_CREAT, S_IRUSR|S_IWUSR);
+	} else {
+		s->log.fd = 2; /* stderr */
+	}
+}
+
+/**
+ * Write log message to disk, or stderr.
+ */
 void
 slog(struct server *s, log_level level,
 		const char *body, size_t sz) {
 
 	const char *c = ".-*#";
-	time_t now = time(NULL);
-	static FILE *fp = NULL;
-	char buf[64];
+	time_t now;
+	char time_buf[64];
 	char msg[124];
-
-
-	static pid_t self = 0;
-	if(!self) self = getpid();
+	char line[256]; /* bounds are checked. */
+	int line_sz, ret;
 
 	if(level > s->cfg->verbosity) return; /* too verbose */
 
-	pthread_spin_lock(&s->log_lock);
-
-	if(!fp) fp = (s->cfg->logfile == NULL) ? stdout : fopen(s->cfg->logfile, "a");
-	if(!fp) goto end;
+	if(!s->log.fd) return;
 
 	/* limit message size */
 	sz = sz ? sz:strlen(body);
 	snprintf(msg, sz + 1 > sizeof(msg) ? sizeof(msg) : sz + 1, "%s", body);
 
-	strftime(buf,sizeof(buf),"%d %b %H:%M:%S",localtime(&now));
-	fprintf(fp,"[%d] %s %c %s\n", (int)self, buf, c[level], msg);
-	fflush(fp);
+	/* get current time */
+	now = time(NULL);
+	strftime(time_buf, sizeof(time_buf), "%d %b %H:%M:%S", localtime(&now));
+
+	/* generate output line. */
+	line_sz = snprintf(line, sizeof(line),
+		"[%d] %s %d %s\n", (int)s->log.self, time_buf, c[level], msg);
+
+	/* write to log and flush to disk. */
+	ret = write(s->log.fd, line, line_sz);
+	ret = fsync(s->log.fd);
 
-end:
-	pthread_spin_unlock(&s->log_lock);
+	(void)ret;
 }
diff --git a/slog.h b/slog.h
index ae61bd3..b44804c 100644
--- a/slog.h
+++ b/slog.h
@@ -11,6 +11,9 @@ typedef enum {
 
 struct server;
 
+void
+slog_init(struct server *s);
+
 void slog(struct server *s, log_level level,
 		const char *body, size_t sz);