[master] 751665662 document backend.list

[Nils Goroll]

commit 75166566231624195d0d5a5b28b887587ffb5b91
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Feb 21 09:47:00 2019 +0100

    document backend.list

diff --git a/include/tbl/cli_cmds.h b/include/tbl/cli_cmds.h
index 5350a7194..0bc1e0f0f 100644
--- a/include/tbl/cli_cmds.h
+++ b/include/tbl/cli_cmds.h
@@ -272,6 +272,22 @@ CLI_CMD(BACKEND_LIST,
 	"List backends.\n",
 	"  ``-p`` also shows probe status.\n\n"
 	"  ``-j`` specifies JSON output.\n\n"
+	"  Unless ``-j`` is specified for JSON output, "
+	" the output format is four columns of dynamic width, "
+	" separated by white space with the fields:\n\n"
+	"  * Backend name\n\n"
+	"  * Admin: How health state is determined:\n\n"
+	"    * healthy: Set healthy through backend.set_health.\n\n"
+	"    * sick: Set sick through backend.set_health.\n\n"
+	"    * probe: Health state determined by a probe.\n\n"
+	"    * deleted: Backend has been deleted, but not yet cleaned up.\n\n"
+	/* XXX #2896 TBD */
+	"  * Probe: Summary of probe checks:\n\n"
+	"    * healthy\n\n"
+	"    * sick\n\n"
+	"    * x/y {good,bad}: The backend is good or bad by x/y measure (e.g."
+	" probes or number of backends in a director\n\n"
+	"  * Last change: Timestamp when the health state last changed.\n\n"
 	"  The health state reported here is generic. A backend's health "
 	"may also depend on the context it is being used in (e.g. "
 	"the object's hash), so the actual health state as visible "