Configure zed's diagnosis engine with vdev properties

Introduce four new vdev properties:
    checksum_n
    checksum_t
    io_n
    io_t

These properties can be used for configuring the thresholds of zed's
diagnosis engine and are interpeted as <N> events in T <seconds>.

When this property is set to a non-default value on a top-level vdev,
those thresholds will also apply to its leaf vdevs. This behavior can be
overridden by explicitly setting the property on the leaf vdev.

Note that, these properties do not persist across vdev replacement. For
this reason, it is advisable to set the property on the top-level vdev
instead of the leaf vdev.

The default values for zed's diagnosis engine (10 events, 600 seconds)
remains unchanged.

Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Reviewed-by: Allan Jude <[email protected]>
Signed-off-by: Rob Wing <[email protected]>
Sponsored-by: Seagate Technology LLC
Closes #13805 

1 files changed, 14 insertions, 3 deletions

diff --git a/man/man7/vdevprops.7 b/man/man7/vdevprops.7
index af5d26f6b..6eebfa006 100644
--- a/man/man7/vdevprops.7
+++ b/man/man7/vdevprops.7
@@ -43,7 +43,8 @@ section, below.
 .Ss Native Properties
 Every vdev has a set of properties that export statistics about the vdev
 as well as control various behaviors.
-Properties are NOT inherited from top-level vdevs.
+Properties are not inherited from top-level vdevs, with the exception of
+checksum_n, checksum_t, io_n, and io_t.
 .Pp
 The values of numeric properties can be specified using human-readable suffixes
 .Po for example,
@@ -114,9 +115,19 @@ The cumulative size of all operations of each type performed by this vdev
 If this device is currently being removed from the pool
 .El
 .Pp
-The following native properties can be used to change the behavior of a ZFS
-dataset.
+The following native properties can be used to change the behavior of a vdev.
 .Bl -tag -width "allocating"
+.It Sy checksum_n , checksum_t , io_n , io_t
+Tune the fault management daemon by specifying checksum/io thresholds of <N>
+errors in <T> seconds, respectively.
+These properties can be set on leaf and top-level vdevs.
+When the property is set on the leaf and top-level vdev, the value of the leaf
+vdev will be used.
+If the property is only set on the top-level vdev, this value will be used.
+The value of these properties do not persist across vdev replacement.
+For this reason, it is advisable to set the property on the top-level vdev -
+not on the leaf vdev itself.
+The default values are 10 errors in 600 seconds.
 .It Sy comment
 A text comment up to 8192 characters long
 .It Sy bootsize