CephFS for early adopters

This pages provides guidance for early adoption of CephFS by users with an appetite for adventure. While work is ongoing to build the scrubbing and disaster recovery tools needed to run CephFS in demanding production environments, it is already useful for community members to try CephFS and provide bug reports and feedback.

Setup instructions

Please see the instructions at Ceph Filesystem.

Most stable configuration

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:

  • Snapshots are disabled by default, unless they are enabled explicitly by an administrator using the allow_new_snaps setting.
  • Ceph will use a single active MDS unless an administrator explicitly sets max_mds to a value greater than 1. Note that creating additional MDS daemons (e.g. with ceph-deploy mds create) is okay, as these will by default simply become standbys. It is also fairly safe to enable standby-replay mode.

Which client?

The fuse client is the easiest way to get up to date code, 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).

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 http://tracker.ceph.com. For more general queries please write to the ceph-users mailing list.