add _MINIO_SERVER_DEBUG env for enabling debug messages (#11128)

cmd/background-newdisks-heal-ops.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/dustin/go-humanize"
 	"github.com/minio/minio/cmd/logger"
+	"github.com/minio/minio/pkg/console"
 )
 
 const (
@@ -140,6 +141,10 @@ wait:
 				}
 			}
 
+			if serverDebugLog {
+				console.Debugf("disk check timer fired, attempting to heal %d drives\n", len(healDisks))
+			}
+
 			// heal only if new disks found.
 			for _, endpoint := range healDisks {
 				disk, format, err := connectEndpoint(endpoint)