Shared Filesystem (CephFS)

Introduction

EIDF allows projects with storage space allocated on our CephFS filesystem to mount that space on different compute resources such as EIDF Virtual Machines Service (VMS).

Mounting is done at a project level, so the whole project CephFS tree is mounted. For users who have used our Cerebras or Cirrus services, the whole of the top-level project directory is mounted, e.g. /home/eidf124 on Cirrus is the same as /home/eidf124 on the VM, and users can manipulate files in that directory.

Pre-requisites

To mount CephFS on a VM:

1. The project must have space allocated on CephFS.
2. A mount key must be created exist. PI's should contact the EIDF helpdesk to have this created.

If both pre-requisites are met, PIs and PMs will be able to see the Mount button under CephFS Mounts in the project management page in the EIDF portal.

Mount button displayed in project management page

Mounting CephFS on a VM

When CephFS is mounted on a VM, it can become the home directory for users logging into that VM. PIs and PMs can enable this mounting for individual VMs via the management page in the Portal.

Warning

Mounting CephFS on a VM where users have superuser (sudo) permissions will allow them to see and manipulate files belonging to other users.

Note

If there is existing data in the VM-local /home, it will be moved to /local-home before mounting. You will have to manually move this data to the mounted home if you wish it accessible by users without superuser permissions.
If your VM runs Ubuntu and you don't mount at /home the target location MUST be empty. A non-empty mountpoint will cause the mount to fail.

To mount CephFS on a VM:

1. Click the Mount button in the project management page under CephFS (see screenshot above).
2. Follow the instructions, selecting either to mount as /home or specifying an alternative mount location
3. Select the VMs on which to mount CephFS at the specified location.
4. Click Submit

Example mounting page for project eidf124