CRDS PUB Server Freeze and Deprecation

Why and When

As of November 10, 2022, all observers should use the standard CRDS OPS server for JWST calibration reference files:

The PUB server:

was set up in anticipation of rapid reference file updates during commissioning and Cycle 1. However, due to the trouble-free commissioning process, the smooth transition to science operations, and the subsequent confusion that has resulted from having two servers, it has been decided that the PUB server is no longer needed and will be decommissioned. To make this transition as smooth as possible, this update will take place in stages.

On November 10, 2022, all observers should begin to transition to using only the CRDS OPS server, See the software documentation for instructions about how to configure CRDS.

On December 2nd, access to the PUB server will no longer be available externally. The frozen PUB database will be maintained internally for 3 months. On March 1, the PUB server will be fully decommissioned and the institute will retain an internal archive of the maps and calibration reference files. Observers who wish to use historical files from the PUB server in the future will need to file a JWST Pipeline help desk ticket to access the information.

Part of the decommissioning process will include establishing guidance for how best to maintain reproducibility for new papers and for already-published papers that used the PUB server. This information will be included in a new JDox page, currently in preparation. Visit the JDox site for new information concerning JWST.

Transition Procedure

If using the PUB server, there are two simple tasks that need to be done to ensure a successful transition from using the PUB server to the JWST OPS server.

First, the folder containing the local CRDS cache, pointed to by the environment variable CRDS_PATH, should be cleared of all old CRDS information.

If created appropriately, the folder that CRDS_CACHE points to should contain ONLY CRDS content. The suggested way of ensuring a new, empty cache, is to create a new folder. For example, to create a CRDS cache folder under a user’s home folder, using Linux, the command is:

$ mkdir $HOME/crds_cache

Then set CRDS_PATH to point to this new, empty folder:

$ export CRDS_PATH=$HOME/crds_cache

The important point is that whatever folder is to be used to hold the CRDS cache should initially be empty; no other content should be present in the folder.

Older CRDS cache folders are no longer needed and can be removed as the user sees fit.

It does not matter what the folder is called, nor where it is located, as long as the user has access permissions to that folder. The location of the CRDS cache should contain sufficient space to hold the references. Current suggested minimum of free space is 100GB.

Second, ensure that the environment variable CRDS_SERVER_URL is pointing to the JWST OPS server,


Following these two steps ensures that further calibration processing will use references from the standard CRDS server.