ECMWF’s Data Handling System moves from Reading to Bologna

After years of planning and a huge amount of organisation, this important move went without a hitch.

In the autumn of 2022, ECMWF’s Data Handling System (DHS) was moved to our new data centre in Bologna, Italy.

The DHS is used to store and access ECMWF’s real-time forecasts, as well as other meteorological data and user files. It plays a crucial role in the production and delivery of our operational forecasts.

The DHS comprises the Meteorological Archival and Retrieval System (MARS), which holds 500 billion meteorological fields, and ECMWF’s file storage system (ECFS), which is used to store user files. To support these two applications, ECMWF runs the high-performance storage system (HPSS), which manages the automatic tape libraries and disk storage. More than 10,000 scripts run every day to access MARS and the ECFS, with two million requests per day for data storage/retrieval.

Moving the whole DHS to Bologna was the only cost-effective option, but it would involve some disruption. The highest priority was to ensure that there was no interruption to our operational forecasts. A temporary DHS was set up in Bologna and work began back in 2017 to identify data flows essential to operations.

A series of dry runs were carried out in the first half of 2022 to simulate the shut-down of the Reading DHS and to ensure that all the data needed to continue our operational forecast service had been included in the temporary DHS. Feedback from our Member and Co-operating States and other users was invaluable in helping us fine-tune the arrangements.

We worked hard to keep users well informed about the reduced access to some data that would occur during the move.

The move began on 8 September 2022. Access to the DHS in Reading was disabled and the temporary DHS in Bologna took over the storage and retrieval of essential data.

In Reading, many thousands of tapes had to be scanned and sorted. Tape libraries, disk systems and servers had to be dismantled and all equipment packed, labelled and loaded onto lorries for the journey across Europe.

On arrival in Bologna, tape libraries had to be re-assembled, calibrated and tested. All cartridges had to be inserted back into the tape libraries, each of the 24,000 cartridges in the correct tape library! Servers had to be racked, disks re-assembled, and all equipment gradually brought back online.

The equipment from Reading supplemented new equipment already set up at the Bologna data centre, giving us enhanced data handling capability for the future. We have now increased from three to eight tape libraries, for example.

On 11 November 2022, the DHS was brought fully into production in its new home in Bologna, thanks to the work of many ECMWF staff.

The DHS move in numbers:
700 petabytes of data   150 servers
3 tape libraries290 tape drives
17 disk systems24,000 tape cartridges


Watch a short film showing the DHS move from Reading to Bologna, produced by Manuel Fuentes, Team Leader in our Data Archives and Dissemination Services Team.

Background image photographer: Stefano Marzoli