some suggestions on the documentation
> On November 28, 2018 at 11:33 AM Thomas Lamprecht <[email protected]> > wrote: > > > Signed-off-by: Thomas Lamprecht <[email protected]> > --- > > changes v1 -> v2: > * address (almost all of) Alwin's comments, thanks! > * minor additions, rewording. > > pveceph.adoc | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 118 insertions(+) > > diff --git a/pveceph.adoc b/pveceph.adoc > index 4132545..a8eab8a 100644 > --- a/pveceph.adoc > +++ b/pveceph.adoc > @@ -92,6 +92,7 @@ the ones from Ceph. > WARNING: Avoid RAID controller, use host bus adapter (HBA) instead. > > > +[[pve_ceph_install]] > Installation of Ceph Packages > ----------------------------- > > @@ -415,6 +416,123 @@ mkdir /etc/pve/priv/ceph > cp /etc/ceph/ceph.client.admin.keyring > /etc/pve/priv/ceph/my-ceph-storage.keyring > ---- > > +[[pveceph_fs]] > +CephFS > +------ > + > +Ceph provides also a filesystem running on top of the same object storage as > +RADOS block devices do. A **M**eta**d**ata **S**erver (`MDS`) is used to map > +the RADOS backed objects to files and directories, allowing to provide a > +POSIX-compliant replicated filesystem. This allows one to have a clustered > +highly available shared filesystem in an easy way if ceph is already used. > Its > +Metadata Servers guarantee that files get balanced out over the whole Ceph > +cluster, this way even high load will not overload a single host, which can > be > +be an issue with traditional shared filesystem approaches, like `NFS`, for > +example. > + > +{pve} supports both, using an existing xref:storage_cephfs[CephFS as > storage]) > +to save backups, ISO files or container templates and creating a > +hyper-converged CephFS itself. > + > + > +[[pveceph_fs_mds]] > +Metadata Server (MDS) > +~~~~~~~~~~~~~~~~~~~~~ > + > +CephFS needs at least one **M**eta**d**ata **S**erver (MDS) to be configured > +and running to be able to work. One can simply create one through the {pve} > web > +GUI's `Node -> CephFS` panel or on the command line with: s/**M**eta**d**ata **S**erver// s/\(MDS\)/`MDS` > + > +---- > +pveceph mds create > +---- > + > +Multiple metadata server can be created in a cluster. But, with the default s/server/servers s/But,/But > +settings only one will be active at any time. If a MDS, or its node, becomes s/will/can s/a MDS/an MDS > +unresponsive or even crashes, another `standby` MDS will get promoted to s/or even crashes/\(or crashes\) > +`active`. One can speed the handover between the active and a standby MDS up > by s/speed/speed up s/handover/hand-over > +using the 'hotstandby' parameter option on create or, if you have already > +created it you may set add: s/create or,/create, or s|set add|set/add > + > +---- > +mds standby replay = true > +---- > + > +in the ceph.conf respective MDS section. With this enabled this specific MDS s/enabled/enabled, > +will always poll the active one, so that it can take over faster as it is in > a > +`warm' state. But, naturally, the active polling will cause some additional s/But,/But > +performance impact on your system and active `MDS`. > + > +Multiple Active MDS > +^^^^^^^^^^^^^^^^^^^ > + > +Since Luminous (12.2.x) you can also have multiple active metadata servers > +running, but this is normally only useful for a high count on parallel > clients, > +as else the `MDS` seldom is the bottleneck. If you want to set this up please > +refer to the ceph documentation. footnote:[Configuring multiple active MDS > +daemons http://docs.ceph.com/docs/mimic/cephfs/multimds/] > + > +[[pveceph_fs_create]] > +Create a CephFS > +~~~~~~~~~~~~~~~ > + > +With {pve}'s CephFS integration into you can create a CephFS easily over the > +Web GUI, the CLI or an external API interface. Some prerequisites are needed s/needed/required > +for this to work: > + > +.Prerequisites for a successful CephFS setup: > +- xref:pve_ceph_install[Install Ceph packages], if this was already done some > + time ago you might want to rerun it on an up to date system to ensure that > + also all CephFS related packages get installed. > +- xref:pve_ceph_monitors[Setup Monitors] > +- xref:pve_ceph_monitors[Setup your OSDs] > +- xref:pveceph_fs_mds[Setup at least one MDS] > + > +After this got all checked and done you can simply create a CephFS through > +either the Web GUI's `Node -> CephFS` panel or the command line tool > `pveceph`, > +for example with: > + > +---- > +pveceph fs create --pg_num 128 --add-storage > +---- maybe add --name as well? > + > +This creates a CephFS named `'cephfs'' using a pool for its data named > +`'cephfs_data'' with `128` placement groups and a pool for its metadata named > +`'cephfs_metadata'' with one quarter of the data pools placement groups > (`32`). > +Check the xref:pve_ceph_pools[{pve} managed Ceph pool chapter] or visit the > +Ceph documentation for more information regarding a fitting placement group > +number (`pg_num`) for your setup footnote:[Ceph Placement Groups > +http://docs.ceph.com/docs/mimic/rados/operations/placement-groups/]. > +Additionally, the `'--add-storage'' parameter will add the CephFS to the > {pve} > +storage configuration after it was created successfully. > + > +Destroy CephFS > +~~~~~~~~~~~~~~ > + > +WARN: Destroying a CephFS will render all its data unusable, this cannot be > +undone! > + > +If you really want to destroy an existing CephFS you first need to stop, or > +destroy, all metadata server (`M̀DS`). You can destroy them either over the > Web > +GUI or the command line interface, with: > + > +---- > +pveceph mds destroy NAME > +---- > +on each {pve} node hosting a MDS daemon. > + > +Then, you can remove (destroy) CephFS by issuing a: > + > +---- > +ceph rm fs NAME --yes-i-really-mean-it > +---- > +on a single node hosting Ceph. After this you may want to remove the created > +data and metadata pools, this can be done either over the Web GUI or the CLI > +with: > + > +---- > +pveceph pool destroy NAME > +---- > > ifdef::manvolnum[] > include::pve-copyright.adoc[] > -- > 2.19.2 > > > _______________________________________________ > pve-devel mailing list > [email protected] > https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel _______________________________________________ pve-devel mailing list [email protected] https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
