Hello, John!
Thank you very much for your reply and for the provided information! As a follow-up to your email, a few other questions have arisen:- is the http://ceph.com/docs/master/cephfs/ page referring to the current release version (Giant) or to the HEAD (Hammer) version? if it's referring to Giant -- are there any major improvements and fixes for CephFS included in the (upcoming) Hammer release?
- the 'one filesystem per Ceph cluster' sounds like a (possible) drawback, from the flexibility point of view. Is this something which will be (or is currently) worked on?
- regarding the system users created on a CephFS -- if it's still not production ready (according to the first replied bullet), I guess I'll try the Ceph block device functionality, as it seems more appropriate to my needs. Of course, I will post any bugs to the bug tracker.
Thanks, again!
Bogdan
On Mon, Mar 23, 2015 at 12:47 PM, John Spray <john.spray@xxxxxxxxxx> wrote:
On 22/03/2015 08:29, Bogdan SOLGA wrote:
Hello, everyone!Like it says at http://ceph.com/docs/master/cephfs/: " CephFS currently lacks a robust ‘fsck’ check and repair function. Please use caution when storing important data as the disaster recovery tools are still under development". That page was recently updated.
I have a few questions related to the CephFS part of Ceph:
* is it production ready?
Currently you can only have one filesystem per Ceph cluster.
* can multiple CephFS be created on the same cluster? The CephFS
creation <http://docs.ceph.com/docs/master/cephfs/createfs/> page
describes how to create a CephFS using (at least) two pools, but
the mounting <http://docs.ceph.com/docs/master/cephfs/kernel/>
page does not refer to any pool, when mounting the FS;
Yes, when using the fuse client there is a per-directory quota system available, although it is not guaranteed to be completely strict. I don't think there is any documentation for that, but you can see how to use it here:
* besides the pool quota
<http://docs.ceph.com/docs/master/rados/operations/pools/#set-pool-quotas>
setting, are there any means by which a CephFS can have a quota
defined? I have found this
<https://wiki.ceph.com/Planning/Blueprints/Firefly/Cephfs_quota_support>
document, which is from the Firefly release (and it seems only a
draft), but no other references on the matter.
https://github.com/ceph/ceph/blob/master/qa/workunits/fs/quota/quota.sh
In this context namespace means the filesystem tree. So "part of the namespace" means a subdirectory.
* this <http://docs.ceph.com/docs/master/man/8/mount.ceph/> page
refers to 'mounting only a part of the namespace' -- what is the
namespace referred in the page?
Yes.
* can a CephFS be mounted simultaneously from multiple clients?
No recommendation at this stage - it would be interesting for you to try some things and let us know how you get on.
* what would be the recommended way of creating system users on a
CephFS, if a quota is needed for each user? create a pool for each
user? or?
Cheers,
John
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