Mounting CephRDS Buckets as Local Drives

All Users

Graphical clients such as Cyberduck (KB019) are good for moving files. Sometimes you want your CephRDS bucket to appear as a folder or drive instead, so applications (Word, Python, R) can open and save files in it directly.

This article explains how to mount a CephRDS bucket as a local drive on Linux, macOS and Windows with rclone.

Network: CephRDS is reachable from the campus network only. Off campus, connect to the UCR campus VPN (Cisco Secure Client) first.

Before you start: what a mount can and cannot do

A mounted bucket looks like a folder, but it is still object storage reached over the network:

Opening and saving files is slower than on a local disk, especially for many small files.
Some operations behave differently: renaming a large folder copies every object, and file locking is not supported.
Two people editing the same file through separate mounts can overwrite each other's changes.

For bulk transfers, rclone copy or rclone sync (see KB013) is faster and more reliable than copying into a mount.

1. Prerequisites (all operating systems)

Get your keys. You need your CephRDS S3 Access Key ID and Secret Access Key (see KB013).
Install rclone. Download it from rclone.org.
Configure a remote. Run rclone config and create a remote named cephrds, following the steps in KB013. Choose storage type s3 and provider Ceph (not "Amazon S3"), and set the endpoint to https://rds.ucr.edu.

In the commands below, replace my-lab-bucket with your bucket name.

2. Mounting on Linux

Linux supports user-space file systems (FUSE), which rclone uses to mount.

Make sure FUSE is installed. It usually is on current distributions. On Ubuntu or Debian, if it is missing, run sudo apt install fuse3.
Create a mount point. This is an empty folder where your files appear:
```
mkdir -p ~/ceph-drive
```
Mount the bucket:
```
rclone mount cephrds:my-lab-bucket ~/ceph-drive --vfs-cache-mode writes --daemon --log-file ~/ceph-drive-rclone.log
```
--vfs-cache-mode writes caches files locally while you write them and then uploads them, which most applications need to save files correctly. --daemon runs the mount in the background; its messages go to the log file.

Your files now appear in ~/ceph-drive. To unmount:

fusermount3 -u ~/ceph-drive

(On older systems the command is fusermount -u.)

3. Mounting on macOS

On macOS, rclone needs the open-source macFUSE extension.

Install macFUSE from macfuse.github.io. You may need to allow the system extension in System Settings under Privacy & Security during installation.
Use the rclone binary from rclone.org. The Homebrew build of rclone does not support mount.
Create a mount point in Terminal:
```
mkdir -p ~/CephRDS
```

Mount the bucket:

rclone mount cephrds:my-lab-bucket ~/CephRDS --vfs-cache-mode writes --daemon --log-file ~/CephRDS-rclone.log

The bucket appears as a volume you can browse in Finder. To unmount:

umount ~/CephRDS

4. Mounting on Windows

On Windows, rclone needs a file system driver to create a drive letter (such as Z:).

Install WinFsp, the open-source Windows File System Proxy, from winfsp.dev.
Mount the bucket. Open Command Prompt or PowerShell. You do not need to create a folder first; rclone creates the drive letter:
```
rclone mount cephrds:my-lab-bucket Z: --vfs-cache-mode writes
```
Leave the window open while you use the drive. Press Ctrl+C in that window to unmount.

Open File Explorer to find the new Z: drive with your CephRDS data.

5. Graphical alternative (RcloneView)

If you prefer not to use the command line, RcloneView is a third-party graphical interface for rclone on Windows and macOS. You can use it to set up the rds.ucr.edu endpoint and mount a bucket with a button. It is not run or supported by Research Computing; check its licensing and terms before you rely on it.

Questions: research-computing@ucr.edu.

Owner: Research Computing Reviewed: 4 Oct 2026