-REPLACE_DISK_PRI = "replace_primary"
-REPLACE_DISK_SEC = "replace_secondary"
-REPLACE_DISK_ALL = "replace_all"
+REPLACE_DISK_PRI = "replace_on_primary" # replace disks on primary
+REPLACE_DISK_SEC = "replace_on_secondary" # replace disks on secondary
+REPLACE_DISK_CHG = "replace_new_secondary" # change secondary node