# managing ceph

Always refer back to the official documentation at https://docs.ceph.com/en/latest

## adding new cephfs
- create a erasure code profile which will allow you to customise the raid level
    - raid5 with 3 disks? k=2,m=1
    - raid5 with 6 disks? k=5,m=1
    - raid6 with 4 disks? k=2,m=2, etc
- create osd pool using custom profile for data
- create osd pool using default replicated profile for metadata
- enable ec_overwrites for the data pool
- create the ceph fs volume using data/metadata pools
- set ceph fs settings
    - specify minimum number of metadata servers (mds)
    - set fs to be for bulk data
    - set mds fast failover with standby reply


    sudo ceph osd erasure-code-profile set ec_4_1 k=4 m=1
    sudo ceph osd pool create media_data 128 erasure ec_4_1
    sudo ceph osd pool create media_metadata 32 replicated_rule
    sudo ceph osd pool set media_data allow_ec_overwrites true
    sudo ceph osd pool set media_data bulk true
    sudo ceph fs new mediafs media_metadata media_data --force
    sudo ceph fs set mediafs allow_standby_replay true
    sudo ceph fs set mediafs max_mds 2


## creating authentication tokens

- this will create a client keyring named media
- this client will have the following capabilities:
    - mon: read
    - mds:
        - read /
        - read/write /media
        - read/write /common
    - osd: read/write to cephfs_data pool

    sudo ceph auth get-or-create client.media mon 'allow r' mds 'allow r path=/, allow rw path=/media, allow rw path=/common' osd 'allow rw pool=cephfs_data'

## list the authentication tokens and permissions

    ceph auth ls

## change the capabilities of a token

this will overwrite the current capabilities of a given client.user

    sudo ceph auth caps client.media mon 'allow r' mds 'allow rw path=/' osd 'allow rw pool=media_data'