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Fuse mount OSD using COT

How to fuse mount OSD using Ceph Objectstore tool(COT)?​

  • Stop the OSD service that you want to fuse mount

    # systemctl stop <>
    or
    # ceph orch daemon stop osd.<id>

  • Enter the cephadm shell for the OSD ID

    # cephadm shell --name=osd.<id>

    This creates a temporary container which allow us to run COT and CBT tool

  • Create a directory to mount the OSD and run the command

    # ceph-objectstore-tool  --op fuse --data-path /var/lib/ceph/osd/ceph-<id> --mountpoint /mnt/osd<id>

    For example, let's take osd.0

    [ceph: root@asite-0 /]# mkdir /mnt/osd0
    [ceph: root@asite-0 /]# ceph-objectstore-tool  --op fuse --data-path /var/lib/ceph/osd/ceph-0 --mountpoint /mnt/osd0
    mounting fuse at /mnt/osd0 ...

  • Now open another terminal to the host and enter into the temporary container created by cephadm in the previous step

    Since it is a temporary container look for a running container with a randon name which is using ceph image

    #podman ps
    a64a6bb1b732  cp.icr.io/cp/ibm-ceph/ceph-8-rhel9@sha256:ec01c807c67da53f0a3ea271b222a7233b2e43e10e319c0c6c5160755b4d7543                        4 hours ago   Up 4 hours   80/tcp, 5000/tcp, 6789/tcp, 6800/tcp, 6801/tcp, 6802/tcp, 6803/tcp, 6804/tcp, 6805/tcp  nice_perlman

    # podman exec -it nice_perlman bash

  • Now, you can look for the contents in the specific mount point

    # ls /mnt
    # du -sch /mnt/osd0/
    526K	/mnt/osd0/
    526K	total