mirror of
https://github.com/ceph/ceph
synced 2024-12-18 09:25:49 +00:00
89 lines
3.4 KiB
ReStructuredText
89 lines
3.4 KiB
ReStructuredText
|
|
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/>`_.
|