From 9e7a12b470ea1ecc52a878212e017f158014ef6e Mon Sep 17 00:00:00 2001 From: John Spray Date: Thu, 18 May 2017 06:54:13 -0400 Subject: [PATCH] doc: multimds is no longer experimental Signed-off-by: John Spray --- doc/cephfs/experimental-features.rst | 35 +++++++++++++++------------- doc/cephfs/mantle.rst | 1 - 2 files changed, 19 insertions(+), 17 deletions(-) diff --git a/doc/cephfs/experimental-features.rst b/doc/cephfs/experimental-features.rst index bdfa998a99e2c..5e5b414ecbea5 100644 --- a/doc/cephfs/experimental-features.rst +++ b/doc/cephfs/experimental-features.rst @@ -23,22 +23,7 @@ failures within it are unlikely to make non-inlined data inaccessible Inline data has always been off by default and requires setting the "inline_data" flag. -Multi-MDS filesystem clusters ------------------------------ -CephFS has been designed from the ground up to support fragmenting the metadata -hierarchy across multiple active metadata servers, to allow horizontal scaling -to arbitrary throughput requirements. Unfortunately, doing so requires a lot -more working code than having a single MDS which is authoritative over the -entire filesystem namespace. - -Multiple active MDSes are generally stable under trivial workloads, but often -break in the presence of any failure, and do not have enough testing to offer -any stability guarantees. If a filesystem with multiple active MDSes does -experience failure, it will require (generally extensive) manual intervention. -There are serious known bugs. - -Multi-MDS filesystems have always required explicitly increasing the "max_mds" -value and have been further protected with the "allow_multimds" flag for Jewel. + Mantle: Programmable Metadata Load Balancer ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -102,3 +87,21 @@ the ``allow_dirfrags`` flag on the filesystem: ceph fs set allow_dirfrags +Multiple active metadata servers +-------------------------------- + +Prior to the *Luminous* (12.2.x) release, running multiple active metadata +servers within a single filesystem was considered experimental. Creating +multiple active metadata servers is now permitted by default on new +filesystems. + +Filesystems created with older versions of Ceph still require explicitly +enabling multiple active metadata servers as follows: + +:: + + ceph fs set allow_multimds + +Note that the default size of the active mds cluster (``max_mds``) is +still set to 1 initially. + diff --git a/doc/cephfs/mantle.rst b/doc/cephfs/mantle.rst index 8a7d729ac38fe..6ad973e2dbd9a 100644 --- a/doc/cephfs/mantle.rst +++ b/doc/cephfs/mantle.rst @@ -76,7 +76,6 @@ Mantle with `vstart.sh` :: - bin/ceph fs set cephfs allow_multimds true --yes-i-really-mean-it bin/ceph fs set cephfs max_mds 5 bin/ceph fs set cephfs_a balancer greedyspill.lua -- 2.39.5