From 36f33f089bbda9bcc7e451b69413907cce8e3bb6 Mon Sep 17 00:00:00 2001 From: Paul Bourke Date: Tue, 24 Apr 2018 14:07:25 +0100 Subject: [PATCH] Reduce the default values for Ceph pgs Required to keep Ceph working once we move to Luminous 12.2.1 Change-Id: I8d3e56f2053c939ea313c60cc04c0ff79dd27d25 Closes-Bug: 1763356 --- ansible/group_vars/all.yml | 7 +++++-- doc/source/reference/ceph-guide.rst | 12 ++++++++++++ etc/kolla/globals.yml | 7 +++++-- .../notes/reduce-ceph-pgs-27e88e3b6e3b809c.yaml | 13 +++++++++++++ 4 files changed, 35 insertions(+), 4 deletions(-) create mode 100644 releasenotes/notes/reduce-ceph-pgs-27e88e3b6e3b809c.yaml diff --git a/ansible/group_vars/all.yml b/ansible/group_vars/all.yml index 6465d9c111..6a850fbebf 100644 --- a/ansible/group_vars/all.yml +++ b/ansible/group_vars/all.yml @@ -723,8 +723,11 @@ ceph_rule: "default host {{ 'indep' if ceph_pool_type == 'erasure' else 'firstn' ceph_cache_rule: "cache host firstn" # Set the pgs and pgps for pool -ceph_pool_pg_num: 128 -ceph_pool_pgp_num: 128 +# WARNING! These values are dependant on the size and shape of your cluster - +# the default values are not suitable for production use. Please refer to the +# Kolla Ceph documentation for more information. +ceph_pool_pg_num: 8 +ceph_pool_pgp_num: 8 ##################### # VMware support diff --git a/doc/source/reference/ceph-guide.rst b/doc/source/reference/ceph-guide.rst index 401a3c67dd..864a3e13a9 100644 --- a/doc/source/reference/ceph-guide.rst +++ b/doc/source/reference/ceph-guide.rst @@ -126,6 +126,18 @@ RadosGW is optional, enable it in ``/etc/kolla/globals.yml``: .. end +.. note:: + + Regarding number of placement groups (PGs) + + Kolla sets very conservative values for the number of PGs per pool + (`ceph_pool_pg_num` and `ceph_pool_pgp_num`). This is in order to ensure + the majority of users will be able to deploy Ceph out of the box. It is + *highly* recommended to consult the official Ceph documentation regarding + these values before running Ceph in any kind of production scenario. + +.. end + RGW requires a healthy cluster in order to be successfully deployed. On initial start up, RGW will create several pools. The first pool should be in an operational state to proceed with the second one, and so on. So, in the case of diff --git a/etc/kolla/globals.yml b/etc/kolla/globals.yml index 7c0e7dac36..9e56540b4c 100644 --- a/etc/kolla/globals.yml +++ b/etc/kolla/globals.yml @@ -267,8 +267,11 @@ kolla_internal_vip_address: "10.10.10.254" #enable_ceph_rgw_keystone: "no" # Set the pgs and pgps for pool -#ceph_pool_pg_num: 128 -#ceph_pool_pgp_num: 128 +# WARNING! These values are dependant on the size and shape of your cluster - +# the default values are not suitable for production use. Please refer to the +# Kolla Ceph documentation for more information. +#ceph_pool_pg_num: 8 +#ceph_pool_pgp_num: 8 ############################# # Keystone - Identity Options diff --git a/releasenotes/notes/reduce-ceph-pgs-27e88e3b6e3b809c.yaml b/releasenotes/notes/reduce-ceph-pgs-27e88e3b6e3b809c.yaml new file mode 100644 index 0000000000..974b985e4f --- /dev/null +++ b/releasenotes/notes/reduce-ceph-pgs-27e88e3b6e3b809c.yaml @@ -0,0 +1,13 @@ +--- +issues: + - | + As of Ceph Luminous 12.2.1 the maximum number of PGs per OSD before the + monitor issues a warning has been reduced from 300 to 200 PGs. In addition, + Ceph now fails with an error rather than a warning in the case of exeeding + the max value. + In order to allow Kolla to continue to be used out of the box we have + reduced the default values for pg_num and pgp_num from 128 to 8. This will + allow a deploy of Kolla with all possible services enabled and then some, + with the minimum recommended three OSDs. Operators are *highly* + recommended to review the Ceph documentation regarding these values in + order to ensure optimal performance for their own cluster.