Globus is a file transfer software ecosystem widely used in the science and research community. It offers the ability to transfer large amounts of data in parallel and over secure channels between various "endpoints."

Globus in LC

Livermore Computing (LC) has received authorization to set up a Globus endpoint in the Green Zone, available to all users with an LC user account (see User Access). LC's Globus endpoint runs version 5.x of the Globus software, is named "LC Public", and is findable in the Globus Web App.

LC's Green Zone requires all data be approved for general (unlimited) distribution.

Data Restrictions

As stated, data in the Green Zone must be considered generally releasable. Data should go through LLNL's Information Management (IM) process  or have prior agreement to be sharable from an ISSO prior to being put in the Green Zone, even temporarily. More information on this process can be found at Review and Release of Large Datasets.

Endpoint Configuration

LC's Globus endpoint is configured on a cluster called goblin and features the following specifications:

  • 4x Data Transfer Nodes (DTNs), each with
    • 2x Intel Xeon Gold 6226R 2.90GHz CPUs, with 32 cores and 64 threads per node
    • 192 GB DDR4-2933 memory
  • 2.1 PB staging storage (for sending/receiving data through Globus)

The endpoint is set up as a High Assurance endpoint, meaning data transfers must be encrypted. This also means that data transfers to or from and endpoint that does not support encryption will not work.

Staging/Copying Data

The LC Globus endpoint offers a 2.1PB file system, mounted via NFS, for staging data. This file system is mounted as /p/globfs with a directory for each user. This user directory is the default data sharing location in LC's Globus endpoint. Note: The data sharing directory is NOT your home directory.

Because the Globus endpoint does not connect to LC's CZ file systems, data must be copied to and from the CZ and this file system. You may use SSH and SCP/SFTP or other file transfer tools to transfer data between the CZ and goblin. It is recommended to use the oslic cluster for file transfers for maximum bandwidth. Please note that your home directory on goblin is /home/<username> and is intentionally not set up for sharing data. Home directories also have a very limited capacity so data meant for staging should be copied directly to /p/globfs/<username>.

SSH/SFTP to the Globus Cluster

As mentioned above, there are four data transfer nodes in goblin, the cluster that hosts the Globus endpoint. Users may find it helpful to log in to one of the nodes to manually organize or otherwise manipulate their data. The nodes are accessible from the CZ via SSH and SFTP. To log in to the cluster, users should SSH to "goblin.llnl.gov" or "goblin" for short, putting them in their home directory on one of the four DTNs. Remember, the data share directory is at /p/globfs/<username>, not your home directory, and that home directories have limited space. Also note, compute jobs are not allowed on the DTNs.

Using LC Globus

User Access

All LC users can use the LC Globus service in accordance with the aforementioned data restrictions. To access the service, they must first request an account on Goblin, the cluster hosting the LC Globus endpoint. To request an account, please go to LC IDM, select Add OCF Computing Resource Account, set the Item Type as Resource, and select "goblin" as a resource. Add that to the request and submit it.

Navigating the Globus Interface

Globus offers both a Web interface as well as a fully-compatible command-line interface (CLI). This page assumes usage of the Web UI but documentation on the CLI can be found here

To get to the Globus Web App, point your browser to https://app.globus.org

Globus Login
 

Once you hit Continue, you may be automatically logged in to Globus if you have cached credentials on your workstation. Otherwise, follow the prompts and it should redirect you to a LivIT identity management page similar to the one below to authenticate with your LLNL AD credentials:

Globus-LivIT IdM
 

You will then be placed into the Globus file manager as shown below. With the file manager, you can search for Collections -- which are user or administrator-defined collections of files on endpoints around the world.

Globus File Manager
 

From the file manager interface, you can start typing in a Collection name that you wish to browse, whether as a source or a destination. As you type, Globus will show names of existing Collections that match what you have typed. You can then select the one you want, such as "LC Public":

LC Public Endpoint
 

Once you select a Collection, unless it allows anonymous access, you will need to be authenticated in order to see the contents of the Collection. If you have credentials cached on your workstation, you should be transparently logged in to the LC Public Collection. If not, you may be passed to the LLNL IdP to authenticate.

Once authenticated to the LC Public Collection, you will be placed in your default data sharing directory of /p/globfs/<username>. You may also browse to other folders you have permissions to access.

Globus File Manager listing
 

From this view you can browse or manipulate files you have access to. You may also click on the "Transfer or Sync to" link on the right to open a second Collection browser and select another Collection with which to transfer files. You may also choose to "share" a subset of your files to other Globus users, whether at LLNL or not.

Transferring Files

As in the picture below, you can then drag and drop folders and files from one browser to the other to initiate a transfer. Likewise, you can select the files you wish to transfer and click the "Start" button at the top of the browser window.

Globus Drag-n-drop
 

Once a file transfer has started you can monitor it (and see past transfers) via the Activity screen accessed via the icon on the far left. On that screen you can view active and past transfers, debug information, and errors you might have encountered. Note that you should also receive an email on completion of a transfer, notifying you of its success or failure.

Globus Activity
 

Sharing Files (Guest Collections)

Only users with active LC accounts will be able to authenticate to the LC Public endpoint, so in order to share data with collaborators outside of LLNL, you will want to create what is called a Guest Collection. You can set up multiple collections shared with different users. Those users will be able to browse to your guest collection in the Globus File Manager and access those files you granted access to.

To share files, first select the files you wish to share in the File Manager, then click on the "Share" icon on the right panel.

Sharing subset of files
 
You may then create a new collection by clicking "Add Guest Collection":
 
Adding a Guest Collection
 

In the next screen fill out the relevant fields and click "Create Collection":

Creating the Guest Collection
 

You then can click on the "Add Permissions - Share With" link on the right-hand side and in the succeeding screen, select the Globus user(s) you wish to share the dataset with. As you type a name, the Globus Web App should auto-match valid users. By default you are granting read-only permissions, but you can also allow them to write to your collection.

Guest Collection Permissions
Adding users to Guest Collection
 

After adding the user(s), you can then verify in the Collection summary that the user has access. You may also share a link to your collection to users that have already been granted access to it.

Viewing users and permissions of Guest Collection