mount.ceph – 用于挂载 Ceph 文件系统

提纲

mount.ceph [mon1_socket,mon2_socket,…]:/[subdir] dir [ -o options ]

描述

mount.ceph 是在 Linux 主机上挂载 Ceph 文件系统的辅助程序。它只负责把监视器主机名解析为 IP 地址、从硬盘读取认证密钥，大多数实际工作由 Linux 内核客户端组件完成。其实，不需要认证的 Ceph 文件系统无需 mount.ceph 也能挂载，只要指定监视器 IP 地址即可：

mount -t ceph 1.2.3.4:/ mountpoint

mount 命令的第一个参数是设备部分，它包括主机的套接字和 CephFS 内要挂载到挂载点的路径。套接字，格式显然是 ip_address[:port] ，如果没指定端口，就假设是 Ceph 默认的 6789 。多个监视器地址用逗号分隔。要成功地挂载只需一个监视器即可，客户端将从某个能响应的监视器了解到其它的监视器。然而最好指定多个监视器，以免挂载时正好赶上那个监视器挂了。

If the host portion of the device is left blank, then mount.ceph will attempt to determine monitor addresses using local configuration files and/or DNS SRV records. In similar way, if authentication is enabled on Ceph cluster (which is done using CephX) and options secret and secretfile are not specified in the command, the mount helper will spawn a child process that will use the standard Ceph library routines to find a keyring and fetch the secret from it.

A sub-directory of the file system can be mounted by specifying the (absolute) path to the sub-directory right after “:” after the socket in the device part of the mount command.

mount 辅助程序的惯例是前两个选项分别为要挂载的设备和目标路径，其它选项必须位于这些固定参数之后。

选项

基础的

conf

Path to a ceph.conf file. This is used to initialize the Ceph context for autodiscovery of monitor addresses and auth secrets. The default is to use the standard search path for ceph.conf files.

command

fs=<fs-name> Specify the non-default file system to be mounted. Not passing this option mounts the default file system.

command

mds_namespace=<fs-name> A synonym of “fs=” and its use is deprecated.

mount_timeout

整数（秒）。默认：60

name

使用 cephx 认证时的 RADOS 用户名。默认： guest

secret

secret key for use with CephX. This option is insecure because it exposes the secret on the command line. To avoid this, use the secretfile option.

secret

用于 cephx 的密钥。这个选项不安全，因为它把密钥暴露在了命令行，用 secretfile 选项可避免此问题。

secretfile

path to file containing the secret key to use with CephX

recover_session=<no|clean>

Set auto reconnect mode in the case where the client is blacklisted. The available modes are no and clean. The default is no.

  • no: never attempt to reconnect when client detects that it has been

    blacklisted. Blacklisted clients will not attempt to reconnect and their operations will fail too.

  • clean: client reconnects to the Ceph cluster automatically when it detects that it has been blacklisted. During reconnect, client drops dirty data/metadata, invalidates page caches and writable file handles. After reconnect, file locks become stale because the MDS loses track of them. If an inode contains any stale file locks, read/write on the inode is not allowed until applications release all stale file locks.

高级的

cap_release_safety

整数。默认：自行计算

caps_wanted_delay_max

整数，能力释放延迟时间。默认：60

caps_wanted_delay_min

整数，能力释放延迟时间。默认：5

dirstat

用 cat dirname 读取文件信息。默认： off

nodirstat

不用 cat dirname 读取文件信息

ip

本机 IP

noasyncreaddir

读目录时不经过 dcache

nocrc

写入时不做 crc 校验

noshare

创建新客户端例程，而不是和挂载同一集群的例程共享资源。

osdkeepalive

整数。默认：5

osdtimeout

整数（秒）。默认：60

osd_idle_ttl

整数（秒）。默认：60

rasize

整数（字节数），最大预读尺寸，默认： 8388608 (8192*1024)

rbytes

目录的 st_size 报告产生于目录内容的递归尺寸。默认： on

norbytes

目录的 st_size 无需通过递归目录内容来获取。

readdir_max_bytes

整数。默认： 524288 （ 512*1024 ）

readdir_max_entries

整数。默认： 1024

rsize

整数（字节数），最大读尺寸。默认： 16777216 (16*1024*1024)

snapdirname

字符串，为快照的隐藏目录设置个名字。默认： .snap

write_congestion_kb

整数（ kb ），运行中的最大回写量，随可用内存变化。默认：根据可用内存计算

wsize

整数（字节数），最大写尺寸。默认： 16777216 (16*1024*1024) （回写用较小的 wsize 和条带单元）

wsync

Execute all namespace operations synchronously. This ensures that the namespace operation will only complete after receiving a reply from the MDS. This is the default.

nowsync

Allow the client to do namespace operations asynchronously. When this option is enabled, a namespace operation may complete before the MDS replies, if it has sufficient capabilities to do so.

实例

挂载整个文件系统：

mount.ceph :/ /mnt/mycephfs

假设 mount.ceph 安装得没问题， mount(8) 应该能自动调用它：

mount -t ceph :/ /mnt/mycephfs

Mount only part of the namespace/file system:

mount.ceph :/some/directory/in/cephfs /mnt/mycephfs
Mount non-default FS, in case cluster has multiple FSs::

mount -t ceph :/ /mnt/mycephfs2 -o fs=mycephfs2

or

mount -t ceph :/ /mnt/mycephfs2 -o mds_namespace=mycephfs2 # This option name is deprecated.

Pass the monitor host’s IP address, optionally:

mount.ceph 192.168.0.1:/ /mnt/mycephfs

Pass the port along with IP address if it’s running on a non-standard port:

mount.ceph 192.168.0.1:7000:/ /mnt/mycephfs

If there are multiple monitors, passes addresses separated by a comma:

mount.ceph 192.168.0.1,192.168.0.2,192.168.0.3:/ /mnt/mycephfs

If authentication is enabled on Ceph cluster:

mount.ceph :/ /mnt/mycephfs -o name=fs_username

Pass secret key for CephX user optionally:

mount.ceph :/ /mnt/mycephfs -o name=fs_username,secret=AQATSKdNGBnwLhAAnNDKnH65FmVKpXZJVasUeQ==

Pass file containing secret key to avoid leaving secret key in shell’s command history:

mount.ceph :/ /mnt/mycephfs -o name=fs_username,secretfile=/etc/ceph/fs_username.secret

使用范围

mount.ceph 是 Ceph 的一部分，这是个伸缩力强、开源、分布式的存储系统，更多信息参见 http://ceph.com/docs 。

功能适用范围

The recover_session= option was added to mainline Linux kernels in v5.4. wsync and nowsync were added in v5.7.

参考

ceph-fuse(8), ceph(8)