Hi,
Jeff Layton schreef op 2022-02-03 15:36:
On Thu, 2022-02-03 at 15:26 +0100, William Edwards wrote:
Hi,
Jeff Layton schreef op 2022-02-03 14:45:
> On Thu, 2022-02-03 at 12:01 +0100, William Edwards wrote:
> > Hi,
> >
> > I need to set options from
> > https://docs.ceph.com/en/nautilus/cephfs/client-config-ref/ . I assume
> > these should be placed in the 'client' section in ceph.conf.
> >
> > The documentation for Nautilus says that ceph.conf should be placed
> > when
> > FUSE is used, see:
> > https://docs.ceph.com/en/nautilus/cephfs/mount-prerequisites/ .
> > However,
> > ceph.conf is not mentioned on
> > https://docs.ceph.com/en/nautilus/cephfs/fstab/#kernel-driver .
> > Therefore, the clients don't currently have an /etc/ceph/ceph.conf.
> >
> > In contrast, the documentation for Pacific says that there **must** be
> > a
> > ceph.conf in any case: https://docs.ceph.com/en/latest/cephfs/mount
> > -prerequisites/#general-pre-requisite-for-mounting-cephfs
> >
> > Newer Ceph versions contain the command 'ceph config
> > generate-minimal-conf'. I can deduce from the command's code what
> > ceph.conf on the client should look like:
> > https://github.com/ceph/ceph/blob/master/src/mon/ConfigMonitor.cc#L423
> >
> > L428: [global]
> > L429: fsid
> > L430 - L448: mon_host (not sure what 'is_legacy' and 'size() == 1'
> > entail; I guess I'll see)
> > L449: newline
> > L450 - L458: This is deduced from
> > https://github.com/ceph/ceph/blob/a67d1cf2a7a4031609a5d37baa01ffdfef80e993/src/mon/ConfigMap.cc#L98
> > . get_minimal_conf only adds options with the flags FLAG_NO_MON_UPDATE
> > or FLAG_MINIMAL_CONF, but I don't see any 'set_flags' statements in
> > master; so I'm not sure which options have those flags.
> >
> > So the resulting config would contain the global section with 'fsid'
> > and
> > 'mon_host', my custom options in 'client', and possibly 'keyring'.
> >
> > Questions:
> >
> > - Is it acceptable to use a ceph.conf on the kernel client when using
> > a
> > Nautilus cluster? It can be specified as the 'conf' mount option, but
> > as
> > the documentation barely mentions it for kernel clients, I'm not 100%
> > sure.
> > - Is my evaluation of the 'minimal' config correct?
> > - Which options have the FLAG_NO_MON_UPDATE and FLAG_MINIMAL_CONF
> > flags?
> > / Where are flags set?
> >
> > The cluster is running Ceph 14.2.22. The clients are running Ceph
> > 12.2.11. All clients use the kernel client.
> >
>
> The in-kernel client itself does not pay any attention to ceph.conf.
> The
> mount helper program (mount.ceph) will look at that ceph configs and
> keyrings to search for mon addresses and secrets for mounting if you
> don't provide them in the device string and mount options.
Are you saying that the options from
https://docs.ceph.com/en/nautilus/cephfs/client-config-ref/ won't take
effect when using the kernel client?
Yes. Those are ignored by the kernel client.
Thanks. I was hoping to set 'client cache size'. Is there any other way
to set it when using the kernel client? I doubt switching to FUSE will
help in solving the performance issue I'm trying to tackle (which is
what I want to set 'client cache size' for :-) ).
--
With kind regards,
William Edwards
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