This originated from ZFS On Linux, as

https://github.com/zfsonlinux/zfs/commit/d4a72f23863382bdf6d0ae33196f5b5decbc48fd

During scans (scrubs or resilvers), it sorts the blocks in each transaction
group by block offset; the result can be a significant improvement. (On my
test system just now, which I put some effort to introduce fragmentation into
the pool since I set it up yesterday, a scrub went from 1h2m to 33.5m with the
changes.) I've seen similar rations on production systems.

Approved by:	Alexander Motin
Obtained from:	ZFS On Linux
Relnotes:	Yes (improved scrub performance, with tunables)
Differential Revision:	https://reviews.freebsd.org/D15562

1 files changed, 3 insertions, 3 deletions

diff --git a/cddl/contrib/opensolaris/cmd/ztest/ztest.c b/cddl/contrib/opensolaris/cmd/ztest/ztest.c
index 1f6eefab24d5..834a2852ef1f 100644
--- a/cddl/contrib/opensolaris/cmd/ztest/ztest.c
+++ b/cddl/contrib/opensolaris/cmd/ztest/ztest.c
@@ -374,15 +374,15 @@ ztest_info_t ztest_info[] = {
 	{ ztest_fzap,				1,	&zopt_sometimes	},
 	{ ztest_dmu_snapshot_create_destroy,	1,	&zopt_sometimes	},
 	{ ztest_spa_create_destroy,		1,	&zopt_sometimes	},
-	{ ztest_fault_inject,			1,	&zopt_sometimes	},
+	{ ztest_fault_inject,			1,	&zopt_incessant	},
 	{ ztest_ddt_repair,			1,	&zopt_sometimes	},
 	{ ztest_dmu_snapshot_hold,		1,	&zopt_sometimes	},
 	{ ztest_reguid,				1,	&zopt_rarely	},
 	{ ztest_spa_rename,			1,	&zopt_rarely	},
-	{ ztest_scrub,				1,	&zopt_rarely	},
+	{ ztest_scrub,				1,	&zopt_often	},
 	{ ztest_spa_upgrade,			1,	&zopt_rarely	},
 	{ ztest_dsl_dataset_promote_busy,	1,	&zopt_rarely	},
-	{ ztest_vdev_attach_detach,		1,	&zopt_sometimes	},
+	{ ztest_vdev_attach_detach,		1,	&zopt_incessant	},
 	{ ztest_vdev_LUN_growth,		1,	&zopt_rarely	},
 	{ ztest_vdev_add_remove,		1,
 	    &ztest_opts.zo_vdevtime				},