From 3a48cbf245f36306052d004b2a7411ea9d803cd0 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Mon, 29 Oct 2012 13:01:06 -0700 Subject: [PATCH] doc: update fs recommendations More forceful about recommending XFS. More warning about using btrfs in production deployments. Signed-off-by: Sage Weil --- .../file-system-recommendations.rst | 49 ++++++++----------- 1 file changed, 21 insertions(+), 28 deletions(-) diff --git a/doc/config-cluster/file-system-recommendations.rst b/doc/config-cluster/file-system-recommendations.rst index e56943e701c..06971c83e2d 100644 --- a/doc/config-cluster/file-system-recommendations.rst +++ b/doc/config-cluster/file-system-recommendations.rst @@ -23,37 +23,30 @@ your OSD cluster. File Systems ============ -Ceph OSDs depend on the Extended Attributes (XATTRs) of the underlying file -system for: - -- Internal object state -- Snapshot metadata -- RADOS Gateway Access Control Lists (ACLs). - -Ceph OSDs rely heavily upon the stability and performance of the underlying file -system. The underlying file system must provide sufficient capacity for XATTRs. -File system candidates for Ceph include B tree and B+ tree file systems such as: - -- ``btrfs`` -- ``XFS`` - -If you are using ``ext4``, mount your file system to enable XATTRs. You must also -add the following line to the ``[osd]`` section of your ``ceph.conf`` file. :: +Ceph OSDs rely heavily upon the stability and performance of the +underlying file system. + +.. tip:: We currently recommend ``XFS`` for production deployments. + +.. tip:: We recommend ``btrfs`` for testing, development, and any +non-critical deployments. We believe that ``btrfs`` has the correct +feature set and roadmap to serve Ceph in the long-term, but ``XFS`` +and ``ext4`` provide the necessary stability for today's deployments. +``btrfs`` development is proceeding rapidly: users should be +comfortable installing the latest released upstream kernels and be +able to track development activity for critical bug fixes. + +Ceph OSDs depend on the Extended Attributes (XATTRs) of the underlying +file system for various forms of internal object state and metadata. +The underlying file system must provide sufficient capacity for +XATTRs. ``btrfs`` does not bound the total xattr metadata stored with +a file. ``XFS`` has a relatively large limit (64 KB) that most +deployments won't encounter, but the ``ext4`` is too small to be +usable. To use these file systems, you should add the following like +to the ``[osd]`` section of your ``ceph.conf`` file.:: filestore xattr use omap = true -.. tip:: Use ``xfs`` initially and ``btrfs`` when it is ready for production. - - The Ceph team believes that the best performance and stability will come from - ``btrfs.`` The ``btrfs`` file system has internal transactions that keep the - local data set in a consistent state. This makes OSDs based on ``btrfs`` simple - to deploy, while providing scalability not currently available from block-based - file systems. The 64-kb XATTR limit for ``xfs`` XATTRS is enough to accommodate - RDB snapshot metadata and RADOS Gateway ACLs. So ``xfs`` is the second-choice - file system of the Ceph team in the long run, but ``xfs`` is currently more - stable than ``btrfs``. If you only plan to use RADOS and ``rbd`` without - snapshots and without ``radosgw``, the ``ext4`` file system should work just fine. - FS Background Info ================== -- 2.47.3