Chapter 3. Deployment of the Ceph File System As a storage administrator, you can deploy Ceph File Systems (CephFS) in a storage environment and have clients mount those Ceph File Systems to meet the storage needs. Basically, the deployment workflow is three steps: Create Ceph File Systems on a Ceph Monitor node. Create a Ceph client user with the appropriate capabilities, and make the client key available on the node where the Ceph File System will be mounted. Mount CephFS on a dedicated node, using either a kernel client or a File System in User Space (FUSE) client. Prerequisites A running, and healthy Red Hat Ceph Storage cluster. Installation and configuration of the Ceph Metadata Server daemon ( ceph-mds ). 3.1. Layout, quota, snapshot, and network restrictions These user capabilities can help you restrict access to a Ceph File System (CephFS) based on the needed requirements. Important All user capability flags, except rw , must be specified in alphabetical order. Layouts and Quotas When using layouts or quotas, clients require the p flag, in addition to rw capabilities. Setting the p flag restricts all the attributes being set by special extended attributes, those with a ceph. prefix. Also, this restricts other means of setting these fields, such as openc operations with layouts. Example In this example, client.0 can modify layouts and quotas on the file system cephfs_a , but client.1 cannot. Snapshots When creating or deleting snapshots, clients require the s flag, in addition to rw capabilities. When the capability string also contains the p flag, the s flag must appear after it. Example In this example, client.0 can create or delete snapshots in the temp directory of file system cephfs_a . Network Restricting clients connecting from a particular network. Example The optional network and prefix length is in CIDR notation, for example, 10.3.0.0/16 . Additional Resources See the Creating client users for a Ceph File System section in the Red Hat Ceph Storage File System Guide for details on setting the Ceph user capabilities. 3.2. Creating Ceph File Systems You can create multiple Ceph File Systems (CephFS) on a Ceph Monitor node. Prerequisites A running, and healthy Red Hat Ceph Storage cluster. Installation and configuration of the Ceph Metadata Server daemon ( ceph-mds ). Root-level access to a Ceph Monitor node. Root-level access to a Ceph client node. Procedure Configure the client node to use the Ceph storage cluster. Enable the Red Hat Ceph Storage Tools repository: Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Install the ceph-fuse package: Copy the Ceph client keyring from the Ceph Monitor node to the client node: Syntax Replace MONITOR_NODE_NAME with the Ceph Monitor host name or IP address. Example Copy the Ceph configuration file from a Ceph Monitor node to the client node: Syntax Replace MONITOR_NODE_NAME with the Ceph Monitor host name or IP address. Example Set the appropriate permissions for the configuration file: Create a Ceph File System: Syntax Example Repeat this step to create additional file systems. Note By running this command, Ceph automatically creates the new pools, and deploys a new Ceph Metadata Server (MDS) daemon to support the new file system. This also configures the MDS affinity accordingly. Verify access to the new Ceph File System from a Ceph client. Authorize a Ceph client to access the new file system: Syntax Example Note Optionally, you can add a safety measure by specifying the root_squash option. This prevents accidental deletion scenarios by disallowing clients with a uid=0 or gid=0 to do write operations, but still allows read operations. Example In this example, root_squash is enabled for the file system cephfs01 , except within the /volumes directory tree. Important The Ceph client can only see the CephFS it is authorized for. Copy the Ceph user's keyring to the Ceph client node: Syntax Example On the Ceph client node, create a new directory: Syntax Example On the Ceph client node, mount the new Ceph File System: Syntax Example On the Ceph client node, list the directory contents of the new mount point, or create a file on the new mount point. Additional Resources See the Creating client users for a Ceph File System section in the Red Hat Ceph Storage File System Guide for more details. See the Mounting the Ceph File System as a kernel client section in the Red Hat Ceph Storage File System Guide for more details. See the Mounting the Ceph File System as a FUSE client section in the Red Hat Ceph Storage File System Guide for more details. See Ceph File System limitations and the POSIX standards section in the Red Hat Ceph Storage File System Guide for more details. See the Pools chapter in the Red Hat Ceph Storage Storage Strategies Guide for more details. 3.3. Adding an erasure-coded pool to a Ceph File System By default, Ceph uses replicated pools for data pools. You can also add an additional erasure-coded data pool to the Ceph File System, if needed. Ceph File Systems (CephFS) backed by erasure-coded pools use less overall storage compared to Ceph File Systems backed by replicated pools. While erasure-coded pools use less overall storage, they also use more memory and processor resources than replicated pools. Important CephFS EC pools are for archival purpose only. Important For production environments, Red Hat recommends using the default replicated data pool for CephFS. The creation of inodes in CephFS creates at least one object in the default data pool. It is better to use a replicated pool for the default data to improve small-object write performance, and to improve read performance for updating backtraces. Prerequisites A running Red Hat Ceph Storage cluster. An existing Ceph File System. Pools using BlueStore OSDs. Root-level access to a Ceph Monitor node. Installation of the attr package. Procedure Create an erasure-coded data pool for CephFS: Syntax Example Verify the pool was added: Example Enable overwrites on the erasure-coded pool: Syntax Example Verify the status of the Ceph File System: Syntax Example Add the erasure-coded data pool to the existing CephFS: Syntax Example This example adds the new data pool, cephfs-data-ec01 , to the existing erasure-coded file system, cephfs-ec . Verify that the erasure-coded pool was added to the Ceph File System: Syntax Example Set the file layout on a new directory: Syntax Example In this example, all new files created in the /mnt/cephfs/newdir directory inherit the directory layout and places the data in the newly added erasure-coded pool. Additional Resources See The Ceph File System Metadata Server chapter in the Red Hat Ceph Storage File System Guide for more information about CephFS MDS. See the Creating Ceph File Systems section in the Red Hat Ceph Storage File System Guide for more information. See the Erasure Code Pools chapter in the Red Hat Ceph Storage Storage Strategies Guide for more information. See the Erasure Coding with Overwrites section in the Red Hat Ceph Storage Storage Strategies Guide for more information. 3.4. Creating client users for a Ceph File System Red Hat Ceph Storage uses cephx for authentication, which is enabled by default. To use cephx with the Ceph File System, create a user with the correct authorization capabilities on a Ceph Monitor node and make its key available on the node where the Ceph File System will be mounted. Prerequisites A running Red Hat Ceph Storage cluster. Installation and configuration of the Ceph Metadata Server daemon (ceph-mds). Root-level access to a Ceph Monitor node. Root-level access to a Ceph client node. Procedure Log into the Cephadm shell on the monitor node: Example On a Ceph Monitor node, create a client user: Syntax To restrict the client to only writing in the temp directory of filesystem cephfs_a : Example To completely restrict the client to the temp directory, remove the root ( / ) directory: Example Note Supplying all or asterisk as the file system name grants access to every file system. Typically, it is necessary to quote the asterisk to protect it from the shell. Verify the created key: Syntax Example Copy the keyring to the client. On the Ceph Monitor node, export the keyring to a file: Syntax Example Copy the client keyring from the Ceph Monitor node to the /etc/ceph/ directory on the client node: Syntax Replace CLIENT_NODE_NAME with the Ceph client node name or IP. Example From the client node, set the appropriate permissions for the keyring file: Syntax Example Additional Resources See the Ceph user management chapter in the Red Hat Ceph Storage Administration Guide for more details. 3.5. Mounting the Ceph File System as a kernel client You can mount the Ceph File System (CephFS) as a kernel client, either manually or automatically on system boot. Important Clients running on other Linux distributions, aside from Red Hat Enterprise Linux, are permitted but not supported. If issues are found in the CephFS Metadata Server or other parts of the storage cluster when using these clients, Red Hat will address them. If the cause is found to be on the client side, then the issue will have to be addressed by the kernel vendor of the Linux distribution. Prerequisites Root-level access to a Linux-based client node. Root-level access to a Ceph Monitor node. An existing Ceph File System. Procedure Configure the client node to use the Ceph storage cluster. Enable the Red Hat Ceph Storage 7 Tools repository: Red Hat Enterprise Linux 9 Install the ceph-common package: Log into the Cephadm shell on the monitor node: Example Copy the Ceph client keyring from the Ceph Monitor node to the client node: Syntax Replace CLIENT_NODE_NAME with the Ceph client host name or IP address. Example Copy the Ceph configuration file from a Ceph Monitor node to the client node: Syntax Replace CLIENT_NODE_NAME with the Ceph client host name or IP address. Example From the client node, set the appropriate permissions for the configuration file: Choose either automatically or manually mounting. Manually Mounting Create a mount directory on the client node: Syntax Example Mount the Ceph File System. To specify multiple Ceph Monitor addresses, separate them with commas in the mount command, specify the mount point, and set the client name: Note As of Red Hat Ceph Storage 4.1, mount.ceph can read keyring files directly. As such, a secret file is no longer necessary. Just specify the client ID with name= CLIENT_ID , and mount.ceph will find the right keyring file. Syntax Example Note You can configure a DNS server so that a single host name resolves to multiple IP addresses. Then you can use that single host name with the mount command, instead of supplying a comma-separated list. Note You can also replace the Monitor host names with the string :/ and mount.ceph will read the Ceph configuration file to determine which Monitors to connect to. Note You can set the nowsync option to asynchronously execute file creation and removal on the Red Hat Ceph Storage clusters. This improves the performance of some workloads by avoiding round-trip latency for these system calls without impacting consistency. The nowsync option requires kernel clients with Red Hat Enterprise Linux 9.0 or later. Example Verify that the file system is successfully mounted: Syntax Example Automatically Mounting On the client host, create a new directory for mounting the Ceph File System. Syntax Example Edit the /etc/fstab file as follows: Syntax The first column sets the Ceph Monitor host names and the port number. The second column sets the mount point The third column sets the file system type, in this case, ceph , for CephFS. The fourth column sets the various options, such as, the user name and the secret file using the name and secretfile options. You can also set specific volumes, sub-volume groups, and sub-volumes using the ceph.client_mountpoint option. Set the _netdev option to ensure that the file system is mounted after the networking subsystem starts to prevent hanging and networking issues. If you do not need access time information, then setting the noatime option can increase performance. Set the fifth and sixth columns to zero. Example The Ceph File System will be mounted on the system boot. Note As of Red Hat Ceph Storage 4.1, mount.ceph can read keyring files directly. As such, a secret file is no longer necessary. Just specify the client ID with name= CLIENT_ID , and mount.ceph will find the right keyring file. Note You can also replace the Monitor host names with the string :/ and mount.ceph will read the Ceph configuration file to determine which Monitors to connect to. Additional Resources See the mount(8) manual page. See the Ceph user management chapter in the Red Hat Ceph Storage Administration Guide for more details on creating a Ceph user. See the Creating Ceph File Systems section of the Red Hat Ceph Storage File System Guide for details. 3.6. Mounting the Ceph File System as a FUSE client You can mount the Ceph File System (CephFS) as a File System in User Space (FUSE) client, either manually or automatically on system boot. Prerequisites Root-level access to a Linux-based client node. Root-level access to a Ceph Monitor node. An existing Ceph File System. Procedure Configure the client node to use the Ceph storage cluster. Enable the Red Hat Ceph Storage 7 Tools repository: Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Install the ceph-fuse package: Log into the Cephadm shell on the monitor node: Example Copy the Ceph client keyring from the Ceph Monitor node to the client node: Syntax Replace CLIENT_NODE_NAME with the Ceph client host name or IP address. Example Copy the Ceph configuration file from a Ceph Monitor node to the client node: Syntax Replace CLIENT_NODE_NAME with the Ceph client host name or IP address. Example From the client node, set the appropriate permissions for the configuration file: Choose either automatically or manually mounting. Manually Mounting On the client node, create a directory for the mount point: Syntax Example Note If you used the path option with MDS capabilities, then the mount point must be within what is specified by the path . Use the ceph-fuse utility to mount the Ceph File System. Syntax Example Note If you do not use the default name and location of the user keyring, that is /etc/ceph/ceph.client. CLIENT_ID .keyring , then use the --keyring option to specify the path to the user keyring, for example: Example Note Use the -r option to instruct the client to treat that path as its root: Syntax Example Note If you want to automatically reconnect an evicted Ceph client, then add the --client_reconnect_stale=true option. Example Verify that the file system is successfully mounted: Syntax Example Automatically Mounting On the client node, create a directory for the mount point: Syntax Example Note If you used the path option with MDS capabilities, then the mount point must be within what is specified by the path . Edit the /etc/fstab file as follows: Syntax The first column sets the Ceph Monitor host names and the port number. The second column sets the mount point The third column sets the file system type, in this case, fuse.ceph , for CephFS. The fourth column sets the various options, such as the user name and the keyring using the ceph.name and ceph.keyring options. You can also set specific volumes, sub-volume groups, and sub-volumes using the ceph.client_mountpoint option. To specify which Ceph File System to access, use the ceph.client_fs option. Set the _netdev option to ensure that the file system is mounted after the networking subsystem starts to prevent hanging and networking issues. If you do not need access time information, then setting the noatime option can increase performance. If you want to automatically reconnect after an eviction, then set the client_reconnect_stale=true option. Set the fifth and sixth columns to zero. Example The Ceph File System will be mounted on the system boot. Additional Resources The ceph-fuse(8) manual page. See the Ceph user management chapter in the Red Hat Ceph Storage Administration Guide for more details on creating a Ceph user. See the Creating Ceph File Systems section of the Red Hat Ceph Storage File System Guide for details. Additional Resources See Section 2.5, "Management of MDS service using the Ceph Orchestrator" to install Ceph Metadata servers. See Section 3.2, "Creating Ceph File Systems" for details. See Section 3.4, "Creating client users for a Ceph File System" for details. See Section 3.5, "Mounting the Ceph File System as a kernel client" for details. See Section 3.6, "Mounting the Ceph File System as a FUSE client" for details. See Chapter 2, The Ceph File System Metadata Server for details on configuring the CephFS Metadata Server daemon.

Commands:
client.0 key: AQAz7EVWygILFRAAdIcuJ10opU/JKyfFmxhuaw== caps: [mds] allow rwp caps: [mon] allow r caps: [osd] allow rw tag cephfs data=cephfs_a client.1 key: AQAz7EVWygILFRAAdIcuJ11opU/JKyfFmxhuaw== caps: [mds] allow rw caps: [mon] allow r caps: [osd] allow rw tag cephfs data=cephfs_a
client.0 key: AQAz7EVWygILFRAAdIcuJ10opU/JKyfFmxhuaw== caps: [mds] allow rw, allow rws path=/temp caps: [mon] allow r caps: [osd] allow rw tag cephfs data=cephfs_a
client.0 key: AQAz7EVWygILFRAAdIcuJ10opU/JKyfFmxhuaw== caps: [mds] allow r network 10.0.0.0/8, allow rw path=/bar network 10.0.0.0/8 caps: [mon] allow r network 10.0.0.0/8 caps: [osd] allow rw tag cephfs data=cephfs_a network 10.0.0.0/8
subscription-manager repos --enable=rhceph-6-tools-for-rhel-8-x86_64-rpms
subscription-manager repos --enable=rhceph-6-tools-for-rhel-9-x86_64-rpms
dnf install ceph-fuse
scp root@ MONITOR_NODE_NAME :/etc/ceph/ KEYRING_FILE /etc/ceph/
scp root@192.168.0.1:/etc/ceph/ceph.client.1.keyring /etc/ceph/
scp root@ MONITOR_NODE_NAME :/etc/ceph/ceph.conf /etc/ceph/ceph.conf
scp root@192.168.0.1:/etc/ceph/ceph.conf /etc/ceph/ceph.conf
chmod 644 /etc/ceph/ceph.conf
ceph fs volume create FILE_SYSTEM_NAME
ceph fs volume create cephfs01
ceph fs authorize FILE_SYSTEM_NAME CLIENT_NAME DIRECTORY PERMISSIONS
ceph fs authorize cephfs01 client.1 / rw [client.1] key = BQAmthpf81M+JhAAiHDYQkMiCq3x+J0n9e8REK== ceph auth get client.1 exported keyring for client.1 [client.1] key = BQAmthpf81M+JhAAiHDYQkMiCq3x+J0n9e8REK== caps mds = "allow rw fsname=cephfs01" caps mon = "allow r fsname=cephfs01" caps osd = "allow rw tag cephfs data=cephfs01"
ceph fs authorize cephfs01 client.1 / rw root_squash /volumes rw [client.1] key = BQAmthpf81M+JhAAiHDYQkMiCq3x+J0n9e8REK== ceph auth get client.1 [client.1] key = BQAmthpf81M+JhAAiHDYQkMiCq3x+J0n9e8REK== caps mds = "allow rw fsname=cephfs01 root_squash, allow rw fsname=cephfs01 path=/volumes" caps mon = "allow r fsname=cephfs01" caps osd = "allow rw tag cephfs data=cephfs01"
ceph auth get CLIENT_NAME > OUTPUT_FILE_NAME scp OUTPUT_FILE_NAME TARGET_NODE_NAME :/etc/ceph
ceph auth get client.1 > ceph.client.1.keyring exported keyring for client.1 scp ceph.client.1.keyring client:/etc/ceph root@client's password: ceph.client.1.keyring 100% 178 333.0KB/s 00:00
mkdir PATH_TO_NEW_DIRECTORY_NAME
mkdir /mnt/mycephfs
ceph-fuse PATH_TO_NEW_DIRECTORY_NAME -n CEPH_USER_NAME --client-fs=_FILE_SYSTEM_NAME
ceph-fuse /mnt/mycephfs/ -n client.1 --client-fs=cephfs01 ceph-fuse[555001]: starting ceph client 2022-05-09T07:33:27.158+0000 7f11feb81200 -1 init, newargv = 0x55fc4269d5d0 newargc=15 ceph-fuse[555001]: starting fuse
ceph osd pool create DATA_POOL_NAME erasure
ceph osd pool create cephfs-data-ec01 erasure pool 'cephfs-data-ec01' created
ceph osd lspools
ceph osd pool set DATA_POOL_NAME allow_ec_overwrites true
ceph osd pool set cephfs-data-ec01 allow_ec_overwrites true set pool 15 allow_ec_overwrites to true
ceph fs status FILE_SYSTEM_NAME
ceph fs status cephfs-ec cephfs-ec - 14 clients ========= RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS 0 active cephfs-ec.example.ooymyq Reqs: 0 /s 8231 8233 891 921 POOL TYPE USED AVAIL cephfs-metadata-ec metadata 787M 8274G cephfs-data-ec data 2360G 12.1T STANDBY MDS cephfs-ec.example.irsrql cephfs-ec.example.cauuaj
ceph fs add_data_pool FILE_SYSTEM_NAME DATA_POOL_NAME
ceph fs add_data_pool cephfs-ec cephfs-data-ec01
ceph fs status FILE_SYSTEM_NAME
ceph fs status cephfs-ec cephfs-ec - 14 clients ========= RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS 0 active cephfs-ec.example.ooymyq Reqs: 0 /s 8231 8233 891 921 POOL TYPE USED AVAIL cephfs-metadata-ec metadata 787M 8274G cephfs-data-ec data 2360G 12.1T cephfs-data-ec01 data 0 12.1T STANDBY MDS cephfs-ec.example.irsrql cephfs-ec.example.cauuaj
mkdir PATH_TO_DIRECTORY setfattr -n ceph.dir.layout.pool -v DATA_POOL_NAME PATH_TO_DIRECTORY
mkdir /mnt/cephfs/newdir setfattr -n ceph.dir.layout.pool -v cephfs-data-ec01 /mnt/cephfs/newdir
cephadm shell
ceph fs authorize FILE_SYSTEM_NAME client. CLIENT_NAME / DIRECTORY CAPABILITY [/ DIRECTORY CAPABILITY ] PERMISSIONS
ceph fs authorize cephfs_a client.1 / r /temp rw client.1 key = AQBSdFhcGZFUDRAAcKhG9Cl2HPiDMMRv4DC43A==
ceph fs authorize cephfs_a client.1 /temp rw
ceph auth get client. ID
ceph auth get client.1 client.1 key = AQBSdFhcGZFUDRAAcKhG9Cl2HPiDMMRv4DC43A== caps mds = "allow r, allow rw path=/temp" caps mon = "allow r" caps osd = "allow rw tag cephfs data=cephfs_a"
ceph auth get client. ID -o ceph.client. ID .keyring
ceph auth get client.1 -o ceph.client.1.keyring exported keyring for client.1
scp /ceph.client. ID .keyring root@ CLIENT_NODE_NAME :/etc/ceph/ceph.client. ID .keyring
scp /ceph.client.1.keyring root@client01:/etc/ceph/ceph.client.1.keyring
chmod 644 ceph.client. ID .keyring
chmod 644 /etc/ceph/ceph.client.1.keyring
subscription-manager repos --enable=rhceph-6-tools-for-rhel-9-x86_64-rpms
dnf install ceph-common
cephadm shell
scp /ceph.client. ID .keyring root@ CLIENT_NODE_NAME :/etc/ceph/ceph.client. ID .keyring
scp /ceph.client.1.keyring root@client01:/etc/ceph/ceph.client.1.keyring
scp /etc/ceph/ceph.conf root@ CLIENT_NODE_NAME :/etc/ceph/ceph.conf
scp /etc/ceph/ceph.conf root@client01:/etc/ceph/ceph.conf
chmod 644 /etc/ceph/ceph.conf
mkdir -p MOUNT_POINT
mkdir -p /mnt/cephfs
mount -t ceph MONITOR-1_NAME :6789, MONITOR-2_NAME :6789, MONITOR-3_NAME :6789:/ MOUNT_POINT -o name= CLIENT_ID ,fs= FILE_SYSTEM_NAME
mount -t ceph mon1:6789,mon2:6789,mon3:6789:/ /mnt/cephfs -o name=1,fs=cephfs01
mount -t ceph mon1:6789,mon2:6789,mon3:6789:/ /mnt/cephfs -o nowsync,name=1,fs=cephfs01
stat -f MOUNT_POINT
stat -f /mnt/cephfs
mkdir -p MOUNT_POINT
mkdir -p /mnt/cephfs
#DEVICE PATH TYPE OPTIONS MON_0_HOST : PORT , MOUNT_POINT ceph name= CLIENT_ID , MON_1_HOST : PORT , ceph.client_mountpoint=/ VOL / SUB_VOL_GROUP / SUB_VOL / UID_SUB_VOL , fs= FILE_SYSTEM_NAME , MON_2_HOST : PORT :/q[_VOL_]/ SUB_VOL / UID_SUB_VOL , [ ADDITIONAL_OPTIONS ]
#DEVICE PATH TYPE OPTIONS DUMP FSCK mon1:6789, /mnt/cephfs ceph name=1, 0 0 mon2:6789, ceph.client_mountpoint=/my_vol/my_sub_vol_group/my_sub_vol/0, mon3:6789:/ fs=cephfs01, _netdev,noatime
subscription-manager repos --enable=6-tools-for-rhel-8-x86_64-rpms
subscription-manager repos --enable=6-tools-for-rhel-9-x86_64-rpms
dnf install ceph-fuse
cephadm shell
scp /ceph.client. ID .keyring root@ CLIENT_NODE_NAME :/etc/ceph/ceph.client. ID .keyring
scp /ceph.client.1.keyring root@client01:/etc/ceph/ceph.client.1.keyring
scp /etc/ceph/ceph.conf root@ CLIENT_NODE_NAME :/etc/ceph/ceph.conf
scp /etc/ceph/ceph.conf root@client01:/etc/ceph/ceph.conf
chmod 644 /etc/ceph/ceph.conf
mkdir PATH_TO_MOUNT_POINT
mkdir /mnt/mycephfs
ceph-fuse -n client. CLIENT_ID --client_fs FILE_SYSTEM_NAME MOUNT_POINT
ceph-fuse -n client.1 --client_fs cephfs01 /mnt/mycephfs
ceph-fuse -n client.1 --keyring=/etc/ceph/client.1.keyring /mnt/mycephfs
ceph-fuse -n client. CLIENT_ID MOUNT_POINT -r PATH
ceph-fuse -n client.1 /mnt/cephfs -r /home/cephfs
ceph-fuse -n client.1 /mnt/cephfs --client_reconnect_stale=true
stat -f MOUNT_POINT
stat -f /mnt/cephfs
mkdir PATH_TO_MOUNT_POINT
mkdir /mnt/mycephfs
#DEVICE PATH TYPE OPTIONS DUMP FSCK HOST_NAME : PORT , MOUNT_POINT fuse.ceph ceph.id= CLIENT_ID , 0 0 HOST_NAME : PORT , ceph.client_mountpoint=/ VOL / SUB_VOL_GROUP / SUB_VOL / UID_SUB_VOL , HOST_NAME : PORT :/ ceph.client_fs= FILE_SYSTEM_NAME ,ceph.name= USERNAME ,ceph.keyring=/etc/ceph/ KEYRING_FILE , [ ADDITIONAL_OPTIONS ]
#DEVICE PATH TYPE OPTIONS DUMP FSCK mon1:6789, /mnt/mycephfs fuse.ceph ceph.id=1, 0 0 mon2:6789, ceph.client_mountpoint=/my_vol/my_sub_vol_group/my_sub_vol/0, mon3:6789:/ ceph.client_fs=cephfs01,ceph.name=client.1,ceph.keyring=/etc/ceph/client1.keyring, _netdev,defaults