:pve-toplevel:
endif::manvolnum[]
-[thumbnail="gui-ceph-status.png"]
+[thumbnail="screenshot/gui-ceph-status.png"]
{pve} unifies your compute and storage systems, i.e. you can use the same
physical nodes within a cluster for both computing (processing VMs and
http://docs.ceph.com/docs/luminous/start/hardware-recommendations/[Ceph's website].
.Avoid RAID
-While RAID controller are build for storage virtualisation, to combine
-independent disks to form one or more logical units. Their caching methods,
-algorithms (RAID modes; incl. JBOD), disk or write/read optimisations are
-targeted towards aforementioned logical units and not to Ceph.
+As Ceph handles data object redundancy and multiple parallel writes to disks
+(OSDs) on its own, using a RAID controller normally doesn’t improve
+performance or availability. On the contrary, Ceph is designed to handle whole
+disks on it's own, without any abstraction in between. RAID controller are not
+designed for the Ceph use case and may complicate things and sometimes even
+reduce performance, as their write and caching algorithms may interfere with
+the ones from Ceph.
WARNING: Avoid RAID controller, use host bus adapter (HBA) instead.
+[[pve_ceph_install]]
Installation of Ceph Packages
-----------------------------
Creating initial Ceph configuration
-----------------------------------
-[thumbnail="gui-ceph-config.png"]
+[thumbnail="screenshot/gui-ceph-config.png"]
After installation of packages, you need to create an initial Ceph
configuration on just one node, based on your network (`10.10.10.0/24`
Creating Ceph Monitors
----------------------
-[thumbnail="gui-ceph-monitor.png"]
+[thumbnail="screenshot/gui-ceph-monitor.png"]
The Ceph Monitor (MON)
footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/]
Creating Ceph OSDs
------------------
-[thumbnail="gui-ceph-osd-status.png"]
+[thumbnail="screenshot/gui-ceph-osd-status.png"]
via GUI or via CLI as follows:
Creating Ceph Pools
-------------------
-[thumbnail="gui-ceph-pools.png"]
+[thumbnail="screenshot/gui-ceph-pools.png"]
A pool is a logical group for storing objects. It holds **P**lacement
-**G**roups (PG), a collection of objects.
+**G**roups (`PG`, `pg_num`), a collection of objects.
-When no options are given, we set a
-default of **64 PGs**, a **size of 3 replicas** and a **min_size of 2 replicas**
-for serving objects in a degraded state.
+When no options are given, we set a default of **128 PGs**, a **size of 3
+replicas** and a **min_size of 2 replicas** for serving objects in a degraded
+state.
-NOTE: The default number of PGs works for 2-6 disks. Ceph throws a
-"HEALTH_WARNING" if you have too few or too many PGs in your cluster.
+NOTE: The default number of PGs works for 2-5 disks. Ceph throws a
+'HEALTH_WARNING' if you have too few or too many PGs in your cluster.
It is advised to calculate the PG number depending on your setup, you can find
the formula and the PG calculator footnote:[PG calculator
Ceph Client
-----------
-[thumbnail="gui-ceph-log.png"]
+[thumbnail="screenshot/gui-ceph-log.png"]
You can then configure {pve} to use such pools to store VM or
Container images. Simply use the GUI too add a new `RBD` storage (see
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 Metadata Server 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:
+
+----
+pveceph mds create
+----
+
+Multiple metadata servers can be created in a cluster. But with the default
+settings only one can be active at any time. If an MDS, or its node, becomes
+unresponsive (or crashes), another `standby` MDS will get promoted to `active`.
+One can speed up the hand-over between the active and a standby MDS up by using
+the 'hotstandby' parameter option on create, or if you have already created it
+you may set/add:
+
+----
+mds standby replay = true
+----
+
+in the ceph.conf respective MDS section. With this enabled, this specific MDS
+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
+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 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
+----
+
+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
+~~~~~~~~~~~~~~
+
+WARNING: 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 fs rm 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[]
projects / pve-docs.git / blobdiff