Detect a slow raidz child for reads

if it's an persistent outlier then sit out reads for a period

Signed-off-by: Don Brady <[email protected]>

cmd/ztest.c

@@ -7374,6 +7374,13 @@ ztest_run_zdb(uint64_t guid)
 	char *set_gvars_args_joined = join_strings(set_gvars_args, " ");
 	free(set_gvars_args);
 
+	printf("%s -bcc%s%s -G -d -Y -e -y %s -p %s %"PRIu64,
+	    bin,
+	    ztest_opts.zo_verbose >= 3 ? "s" : "",
+	    ztest_opts.zo_verbose >= 4 ? "v" : "",
+	    set_gvars_args_joined,
+	    ztest_opts.zo_dir,
+	    guid);
 	size_t would = snprintf(zdb, len,
 	    "%s -bcc%s%s -G -d -Y -e -y %s -p %s %"PRIu64,
 	    bin,
@@ -7386,7 +7393,7 @@ ztest_run_zdb(uint64_t guid)
 
 	umem_free(set_gvars_args_joined, strlen(set_gvars_args_joined) + 1);
 
-	if (ztest_opts.zo_verbose >= 5)
+//	if (ztest_opts.zo_verbose >= 5)
 		(void) printf("Executing %s\n", zdb);
 
 	fp = popen(zdb, "r");

include/sys/vdev_impl.h

@@ -432,6 +432,8 @@ struct vdev {
 	hrtime_t	vdev_mmp_pending; /* 0 if write finished	*/
 	uint64_t	vdev_mmp_kstat_id;	/* to find kstat entry */
 	uint64_t	vdev_expansion_time;	/* vdev's last expansion time */
+	int		vdev_read_sit_out_iops;	/* iops a slow disk sits out */
+	int		vdev_outlier_count;	/* peer outlier events */
 	list_node_t	vdev_leaf_node;		/* leaf vdev list */
 
 	/*

include/sys/vdev_raidz.h

@@ -60,6 +60,7 @@ void vdev_raidz_checksum_error(zio_t *, struct raidz_col *, abd_t *);
 struct raidz_row *vdev_raidz_row_alloc(int, zio_t *);
 void vdev_raidz_reflow_copy_scratch(spa_t *);
 void raidz_dtl_reassessed(vdev_t *);
+boolean_t vdev_skip_latency_outlier(vdev_t *, zio_flag_t);
 
 extern const zio_vsd_ops_t vdev_raidz_vsd_ops;
 

include/sys/vdev_raidz_impl.h

@@ -121,6 +121,7 @@ typedef struct raidz_col {
 	int rc_shadow_devidx;		/* for double write during expansion */
 	int rc_shadow_error;		/* for double write during expansion */
 	uint64_t rc_shadow_offset;	/* for double write during expansion */
+	uint64_t rc_latency;		/* leaf device scaled latency value */
 } raidz_col_t;
 
 typedef struct raidz_row {

module/zfs/vdev_draid.c

@@ -1993,6 +1993,14 @@ vdev_draid_io_start_read(zio_t *zio, raidz_row_t *rr)
 				rc->rc_force_repair = 1;
 				rc->rc_allow_repair = 1;
 			}
+		} else if (c >= rr->rr_firstdatacol &&
+		    rr->rr_missingdata == 0 &&
+		    vdev_skip_latency_outlier(cvd, zio->io_flags)) {
+			rr->rr_missingdata++;
+			rc->rc_error = SET_ERROR(EAGAIN);
+			rc->rc_tried = 1;
+			rc->rc_skipped = 1;
+			continue;
 		}
 	}