From a85149c40e34b3ccd2aa5f3865bb85d2378d6086 Mon Sep 17 00:00:00 2001 From: Paul Dardeau Date: Thu, 17 Mar 2016 22:12:42 +0000 Subject: [PATCH] Update ring overview for reuse of device ids Change-Id: Ied15706d4cc931b5314001a02457f83e175c5d24 --- doc/source/overview_ring.rst | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/doc/source/overview_ring.rst b/doc/source/overview_ring.rst index b121d37135..a1a72d8508 100644 --- a/doc/source/overview_ring.rst +++ b/doc/source/overview_ring.rst @@ -103,10 +103,14 @@ meta string A general-use field for storing additional information for the ====== ======= ============================================================== Note: The list of devices may contain holes, or indexes set to None, for -devices that have been removed from the cluster. Generally, device ids are not -reused. Also, some devices may be temporarily disabled by setting their weight -to 0.0. To obtain a list of active devices (for uptime polling, for example) -the Python code would look like: ``devices = list(self._iter_devs())`` +devices that have been removed from the cluster. However, device ids are +reused. Device ids are reused to avoid potentially running out of device id +slots when there are available slots (from prior removal of devices). A +consequence of this device id reuse is that the device id (integer value) does +not necessarily correspond with the chronology of when the device was added to +the ring. Also, some devices may be temporarily disabled by setting their +weight to 0.0. To obtain a list of active devices (for uptime polling, for +example) the Python code would look like: ``devices = list(self._iter_devs())`` ************************* Partition Assignment List