On Thu, 2022-02-03 at 16:52 +0100, William Edwards wrote: > 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 :-) ). > No, not really. We don't limit the amount of pagecache in use by a particular mount in the kernel. If you want to limit the amount of pagecache in use, then you have to tune generic VM settings like the /proc/sys/vm/dirty_* settings. Alternately you can investigate cgroups if you want to limit the amount of memory a particular application is allowed to dirty at a time. -- Jeff Layton <jlayton@xxxxxxxxxx> _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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