doc: address review comments

Signed-off-by: Shraddha Agrawal <[email protected]>

Author: shraddhaag

doc/rados/operations/monitoring.rst

@@ -756,19 +756,32 @@ Example output:
 .. prompt:: bash $
 
    POOL       	UPTIME  DOWNTIME  NUMFAILURES  MTBF  MTTR  SCORE 	AVAILABLE
-   rbd            	2m   	21s        	1	2m   21s  0.888889      	1
-   .mgr          	86s    	0s        	0	0s	0s     	1      	1
-   cephfs.a.meta 	77s    	0s        	0	0s	0s     	1      	1
-   cephfs.a.data 	76s    	0s        	0	0s	0s     	1      	1
+   rbd             2m     21s        	1	     2m   21s  0.888889      	1
+   .mgr          	86s    	0s        	0	     0s	  0s     	1      	1
+   cephfs.a.meta 	77s    	0s        	0	     0s	  0s     	1      	1
+   cephfs.a.data 	76s    	0s        	0	     0s	  0s     	1      	1
 
 A pool is considered ``unavailable`` when at least one PG in the pool 
 becomes inactive or there is at least one unfound object in the pool. 
-Otherwise the pool is considered ``available``. 
-
-We first calculate the Mean Time Between Failures (MTBF) and 
-Mean Time To Recover (MTTR) from the uptime and downtime recorded 
-for each pool and arrive at the availability score 
-by finding ratio of MTBF to total time (ie MTTR + MTBF).  
-
-The score is updated every 5 seconds. This interval is currently 
-not configurable. 
+Otherwise the pool is considered ``available``. Depending on the 
+current and previous state of the pool we update ``uptime`` and 
+``downtime`` values: 
+
+================ =============== =============== =================
+ Previous State   Current State   Uptime Update   Downtime Update 
+================ =============== =============== =================
+ Available        Available       +diff time      no update    
+ Available        Unavailable     +diff time      no update
+ Unavailable      Available       +diff time      no update 
+ Unavailable      Unavailable     no update       +diff time 
+================ =============== =============== =================
+
+From the updated ``uptime`` and ``downtime`` values, we calculate 
+the Mean Time Between Failures (MTBF) and Mean Time To Recover (MTTR)
+for each pool. The availability score is then calculated by finding 
+the ratio of MTBF to the total time.  
+
+The score is updated every five seconds. This interval is currently 
+not configurable. Any intermittent changes to the pools that 
+occur between this duration but are reset before we recheck the pool 
+status will not be captured by this feature.