Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/doc/cephfs/best-practices.rst b/doc/cephfs/best-practices.rst
new file mode 100644
index 00000000..06a14ec6
--- /dev/null
+++ b/doc/cephfs/best-practices.rst
@@ -0,0 +1,88 @@
+
+CephFS best practices
+=====================
+
+This guide provides recommendations for best results when deploying CephFS.
+
+For the actual configuration guide for CephFS, please see the instructions
+at :doc:`/cephfs/index`.
+
+Which Ceph version?
+-------------------
+
+Use at least the Jewel (v10.2.0) release of Ceph.  This is the first
+release to include stable CephFS code and fsck/repair tools.  Make sure
+you are using the latest point release to get bug fixes.
+
+Note that Ceph releases do not include a kernel, this is versioned
+and released separately.  See below for guidance of choosing an
+appropriate kernel version if you are using the kernel client
+for CephFS.
+
+Most stable configuration
+-------------------------
+
+Some features in CephFS are still experimental.  See
+:doc:`/cephfs/experimental-features` for guidance on these.
+
+For the best chance of a happy healthy filesystem, use a **single active MDS** 
+and **do not use snapshots**.  Both of these are the default.
+
+Note that creating multiple MDS daemons is fine, as these will simply be
+used as standbys.  However, for best stability you should avoid
+adjusting ``max_mds`` upwards, as this would cause multiple MDS
+daemons to be active at once.
+
+Which client?
+-------------
+
+The FUSE client is the most accessible and the easiest to upgrade to the
+version of Ceph used by the storage cluster, while the kernel client will
+often give better performance.
+
+The clients do not always provide equivalent functionality, for example
+the fuse client supports client-enforced quotas while the kernel client
+does not.
+
+When encountering bugs or performance issues, it is often instructive to
+try using the other client, in order to find out whether the bug was
+client-specific or not (and then to let the developers know).
+
+Which kernel version?
+---------------------
+
+Because the kernel client is distributed as part of the linux kernel (not
+as part of packaged ceph releases),
+you will need to consider which kernel version to use on your client nodes.
+Older kernels are known to include buggy ceph clients, and may not support
+features that more recent Ceph clusters support.
+
+Remember that the "latest" kernel in a stable linux distribution is likely
+to be years behind the latest upstream linux kernel where Ceph development
+takes place (including bug fixes).
+
+As a rough guide, as of Ceph 10.x (Jewel), you should be using a least a
+4.x kernel.  If you absolutely have to use an older kernel, you should use
+the fuse client instead of the kernel client.
+
+This advice does not apply if you are using a linux distribution that
+includes CephFS support, as in this case the distributor will be responsible
+for backporting fixes to their stable kernel: check with your vendor.
+
+Reporting issues
+----------------
+
+If you have identified a specific issue, please report it with as much
+information as possible.  Especially important information:
+
+* Ceph versions installed on client and server
+* Whether you are using the kernel or fuse client
+* If you are using the kernel client, what kernel version?
+* How many clients are in play, doing what kind of workload?
+* If a system is 'stuck', is that affecting all clients or just one?
+* Any ceph health messages
+* Any backtraces in the ceph logs from crashes
+
+If you are satisfied that you have found a bug, please file it on
+`the tracker <http://tracker.ceph.com>`_.  For more general queries please write
+to the `ceph-users mailing list <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com/>`_.