diff --git a/README b/README
index 8b84a08..d6e266a 100644
--- a/README
+++ b/README
@@ -92,6 +92,9 @@
 			rw, offset, length
 			where with rw=0/1 for read/write, and the offset
 			and length entries being in bytes.
+	write_iolog=x	Write an iolog to file 'x' in the same format as iolog.
+			The iolog options are exclusive, if both given the
+			read iolog will be performed.
 	lockmem=x	Lock down x amount of memory on the machine, to
 			simulate a machine with less memory available. x can
 			include k/m/g suffix.
diff --git a/fio-ini.c b/fio-ini.c
index f529757..d515035 100644
--- a/fio-ini.c
+++ b/fio-ini.c
@@ -402,8 +402,12 @@
 
 static int check_str(char *p, char *name, str_cb_fn *cb, struct thread_data *td)
 {
-	char *s = strstr(p, name);
+	char *s;
 
+	if (strncmp(p, name, strlen(name)))
+		return 1;
+
+	s = strstr(p, name);
 	if (!s)
 		return 1;
 
@@ -418,8 +422,12 @@
 
 static int check_strstore(char *p, char *name, char *dest)
 {
-	char *s = strstr(p, name);
+	char *s;
 
+	if (strncmp(p, name, strlen(name)))
+		return 1;
+
+	s = strstr(p, name);
 	if (!s)
 		return 1;
 
@@ -454,6 +462,9 @@
 	char option[128];
 	char *str, *p1, *p2;
 
+	if (strncmp(p, name, strlen(name)))
+		return 1;
+
 	strcpy(option, p);
 	p = option;
 
@@ -634,7 +645,6 @@
 static int str_iolog_cb(struct thread_data *td, char *file)
 {
 	strncpy(td->iolog_file, file, sizeof(td->iolog_file) - 1);
-
 	return 0;
 }
 
@@ -858,7 +868,16 @@
 				continue;
 			}
 			if (!check_str(p, "iolog", str_iolog_cb, td)) {
-				td->iolog = 1;
+				printf("got read iolog\n");
+				td->read_iolog = 1;
+				td->write_iolog = 0;
+				fgetpos(f, &off);
+				continue;
+			}
+			if (!td->read_iolog &&
+			    !check_str(p, "write_iolog", str_iolog_cb, td)) {
+				printf("got write iolog\n");
+				td->write_iolog = 1;
 				fgetpos(f, &off);
 				continue;
 			}
diff --git a/fio.c b/fio.c
index 51cd153..695d754 100644
--- a/fio.c
+++ b/fio.c
@@ -628,17 +628,16 @@
 	td->cur_depth--;
 }
 
-static int fill_io_u(struct thread_data *td, struct io_u *io_u)
+static void write_iolog_put(struct thread_data *td, struct io_u *io_u)
 {
-	/*
-	 * If using an iolog, grab next piece if any available.
-	 */
-	if (td->iolog) {
-		struct io_piece *ipo;
+	fprintf(td->iolog_f, "%d,%llu,%u\n", io_u->ddir, io_u->offset, io_u->buflen);
+}
 
-		if (list_empty(&td->io_log_list))
-			return 1;
+static int read_iolog_get(struct thread_data *td, struct io_u *io_u)
+{
+	struct io_piece *ipo;
 
+	if (!list_empty(&td->io_log_list)) {
 		ipo = list_entry(td->io_log_list.next, struct io_piece, list);
 		list_del(&ipo->list);
 		io_u->offset = ipo->offset;
@@ -648,6 +647,17 @@
 		return 0;
 	}
 
+	return 1;
+}
+
+static int fill_io_u(struct thread_data *td, struct io_u *io_u)
+{
+	/*
+	 * If using an iolog, grab next piece if any available.
+	 */
+	if (td->read_iolog)
+		return read_iolog_get(td, io_u);
+
 	/*
 	 * No log, let the seq/rand engine retrieve the next position.
 	 */
@@ -656,6 +666,13 @@
 
 		if (io_u->buflen) {
 			io_u->ddir = get_rw_ddir(td);
+
+			/*
+			 * If using a write iolog, store this entry.
+			 */
+			if (td->write_iolog)
+				write_iolog_put(td, io_u);
+
 			return 0;
 		}
 	}
@@ -707,7 +724,7 @@
 		return NULL;
 	}
 
-	if (!td->iolog && !td->sequential)
+	if (!td->read_iolog && !td->sequential)
 		mark_random_map(td, io_u);
 
 	td->last_pos += io_u->buflen;
@@ -795,6 +812,13 @@
 	list_add(&ipo->list, entry);
 }
 
+static void write_iolog_close(struct thread_data *td)
+{
+	fflush(td->iolog_f);
+	fclose(td->iolog_f);
+	free(td->iolog_buf);
+}
+
 static int init_iolog(struct thread_data *td)
 {
 	unsigned long long offset;
@@ -803,15 +827,34 @@
 	FILE *f;
 	int rw, i, reads, writes;
 
-	if (!td->iolog)
+	if (!td->read_iolog && !td->write_iolog)
 		return 0;
 
-	f = fopen(td->iolog_file, "r");
+	if (td->read_iolog)
+		f = fopen(td->iolog_file, "r");
+	else
+		f = fopen(td->iolog_file, "w");
+
 	if (!f) {
 		perror("fopen iolog");
+		printf("file %s, %d/%d\n", td->iolog_file, td->read_iolog, td->write_iolog);
 		return 1;
 	}
 
+	/*
+	 * That's it for writing, setup a log buffer and we're done.
+	  */
+	if (td->write_iolog) {
+		td->iolog_f = f;
+		td->iolog_buf = malloc(8192);
+		setvbuf(f, td->iolog_buf, _IOFBF, 8192);
+		return 0;
+	}
+
+	/*
+	 * Read in the read iolog and store it, reuse the infrastructure
+	 * for doing verifications.
+	 */
 	str = malloc(4096);
 	reads = writes = i = 0;
 	while ((p = fgets(str, 4096, f)) != NULL) {
@@ -1837,6 +1880,7 @@
 	td_set_runstate(td, TD_INITIALIZED);
 	sem_post(&startup_sem);
 	sem_wait(&td->mutex);
+	ret = 0;
 
 	if (!td->create_serialize && setup_file(td))
 		goto err;
@@ -1879,14 +1923,14 @@
 			break;
 	}
 
-	ret = 0;
-
 	if (td->bw_log)
 		finish_log(td, td->bw_log, "bw");
 	if (td->slat_log)
 		finish_log(td, td->slat_log, "slat");
 	if (td->clat_log)
 		finish_log(td, td->clat_log, "clat");
+	if (td->write_iolog)
+		write_iolog_close(td);
 
 	if (exitall_on_terminate)
 		terminate_threads(td->groupid);
diff --git a/fio.h b/fio.h
index 4f87fb7..01c8b9b 100644
--- a/fio.h
+++ b/fio.h
@@ -150,9 +150,12 @@
 	unsigned int iodepth;
 	os_cpu_mask_t cpumask;
 	unsigned int jobnum;
-	unsigned int iolog;
+	unsigned int read_iolog;
+	unsigned int write_iolog;
 
 	char iolog_file[256];
+	void *iolog_buf;
+	FILE *iolog_f;
 
 	struct drand48_data bsrange_state;
 	struct drand48_data verify_state;