From fc597e5e3473d7db6548405ce347ca7732832451 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Mon, 14 Jul 2014 09:14:32 -0700 Subject: [PATCH] doc/release-notes: some additional warnings and recommendations against adjusting tunables Several users are having troubles related to the overhead of the data rebalance from adjusting tunables. Signed-off-by: Sage Weil --- doc/release-notes.rst | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/doc/release-notes.rst b/doc/release-notes.rst index 21d59fabb6bce..d52dc81c628d6 100644 --- a/doc/release-notes.rst +++ b/doc/release-notes.rst @@ -273,6 +273,18 @@ Upgrade Sequencing upgrading to v0.80 Firefly. Please refer to the :ref:`Dumpling upgrade` documentation. +* We recommand adding the following to the [mon] section of your + ceph.conf prior to upgrade:: + + mon warn on legacy crush tunables = false + + This will prevent health warnings due to the use of legacy CRUSH + placement. Although it is possible to rebalance existing data + across your cluster (see the upgrade notes below), we do not + normally recommend it for production environments as a large amount + of data will move and there is a significant performance impact from + the rebalancing. + * Upgrade daemons in the following order: #. Monitors @@ -353,9 +365,10 @@ Upgrading from v0.72 Emperor adding 'mon warn on legacy crush tunables = false' to ceph.conf and restarting the monitors. Alternatively, you can switch to the new tunables with 'ceph osd crush tunables firefly,' but keep in mind - that this will involve moving a significant portion of the data + that this will involve moving a *significant* portion of the data already stored in the cluster and in a large cluster may take - several days to complete. + several days to complete. We do not recommend adjusting tunables on a + production cluster. * We now default to the 'bobtail' CRUSH tunable values that are first supported by Ceph clients in bobtail (v0.56) and Linux kernel version v3.9. If you -- 2.39.5