West Cambridge Data Centre Upgrade and Planned Disruption June 2025 - April 2026

Important

  • This page describes the timeline and milestones of the West Cambridge Data Centre upgrade project, and the expected impacts on services run from the Research Computing Data Hall (CSD3, Dawn, SRCP, RFS, RDS, RCS, Arcus/IRIS/SKA/Gaia).

Last updated: Mon Oct 27 13:35:02 GMT 2025

Overview

The project to upgrade the power and cooling systems in the West Cambridge Data Centre (WCDC) is now in its implmentation phase and is expected to require several disruptions to services run from it, between June 2025 and its completion in early 2026. The purpose of the project is to provide a sustainable increase to electrical and cooling capacity and so allow the expansion of services. There have already been some unexpected service disruptions in the course of the execution of the project, and more are possible as it progresses. Current information about the expected impacts to service and the status of the upgrade will be made available on this page.

Current Status

WCDC Power/Cooling Capacity
  • 1.2MW
CSD3
  • Available
Dawn
  • Available
RFS/RDS/RCS
  • Available
IRIS/Gaia Hypervisors
  • Available
Windows SRCP
  • Available
Linux SRCP
  • Available
Arcus/Other IRIS hypervisors
  • Available

Key Dates

October - December 2025

Disruption to rear door cooling, row by row, to flush chilled water pipework and reconnect it to the new cooling system.
  • We expect to be able to manage around this with minimal service impact.
  • This work will increase the resilience of the cooling, removing some single points of failure as well as increasing the cooling capacity ready for when the power capacity is increased.

October 2025

Thursday October 23rd 2025
  • Chilled water circuit flushing and reconnections to the new cooling system commence, row by row in the data hall.
Tuesday October 28th 2025
  • 09:00-12:00 Periodic generator testing will take place. Research Computing Services will be required to reduce power consumption to 800KW during this period.

November 2025

Monday 10th - Wednesday 12th November 2025
  • Generator servicing 09:00-16:00 daily. This will require Research Computing Services to reduce power consumption to 800KW during this period on each day.
Tuesday 11th November 2025
  • 10:00-15:00 Network maintenance. This may lead to some brief network blips/freezes when new network switches are connected.
Tuesday 25th - Wednesday 26th November 2025
  • Two days running on generator to enable the connection of a new transformer. This will require Research Computing Services to reduce power consumption to 800KW throughout this period.

January 2026

UPS maintenance - TBC
  • Timing and impact to be confirmed.
Tuesday 27th January 2026
  • Black Building Test (BBT). This is a periodic test which will require Research Computing Services to reduce power consumption to 800KW.

February 2026

Tuesday 24th February 2026
  • 09:00-12:00 ​Periodic generator testing will take place. Research Computing Services will be required to reduce power consumption to 800KW during this period.

March 2026

Tuesday 24th March 2026
  • Black Building Test (BBT). This is a periodic test which will require Research Computing Services to reduce power consumption to 800KW.
24th -31st March 2026
  • Migration of DH1 Rows C-F [1] to new power infrastructure including new UPS, generators and transformer.
  • This will disrupt high power systems which are not resilient​, which is likely to be manageable by changing which nodes are available.
  • DH1 capacity increases to 1.8MW.

April 2026

Two week period - mid April (possibly significantly later) - TBC.
  • Connections to be established between the new and old power infrastructures to enable resilience across transformers. Full commissioning of control sequences for switchover between supplies will take place.
  • This is expected to require at least a 3 day full outage of the WCDC. The remainder of the two week period will be at-risk and a shut down may be recommended. Details are still TBC.

Questions

If you have any questions about these developments or have issues before, during or after these periods, please contact us at support@hpc.cam.ac.uk.

Change Log

  • [27/10/2025] (13:35) Network maintenance 11th November.
  • [24/10/2025] (10:45) Further details of October-April planned disruptions added.
  • [08/10/2025] (17:30) Network maintenance 14 October.
  • [06/10/2025] (12:30) Network maintenance 7-8 October.
  • [20/09/2025] (03:15) Maintenance complete.
  • [19/09/2025] (18:40) Maintenance (mostly) complete.
  • [19/09/2025] (17:00) Maintenance progress.
  • [16/09/2025] (13:16) Update notice of 17-19 Sept downtime.
  • [03/09/2025] (14:45) Update post disruptive planned work 3rd Sept
  • [03/09/2025] (09:30) Tidy up to remove info from pre-September
  • [02/09/2025] (17:00) General updates to schedule including one day outage to some systems on 3rd Sept
  • [21/08/2025] (17:00) Closure of major incident.
  • [20/08/2025] (19:20) Status update - continuing to prove cooling.
  • [19/08/2025] (21:00) Status update - artificial load.
  • [15/08/2025] (17:15) Status update.
  • [14/08/2025] (18:00) Update on chiller repair.
  • [13/08/2025] (16:00) Update on partial sevice resumption.
  • [13/08/2025] (14:00) Partial resumption of HPC service.
  • [13/08/2025] (09:45) Update on chiller 2 high pressure fault.
  • [12/08/2025] (15:00) Update on chiller repair.
  • [12/08/2025] (11:00) Update on chiller repair.
  • [12/08/2025] (10:00) Update on chiller repair.
  • [11/08/2025] (15:35) Update on phased load increase on Tuesday.
  • [11/08/2025] (09:15) Partial resumption of service (short jobs only).
  • [08/08/2025] (15:55) Weekend suspension of service.
  • [08/08/2025] Reduced capacity while cooling failure remains under investigation.
  • [07/08/2025] (18:50) Chiller failure update - no jobs running overnight.
  • [07/08/2025] Chiller failure.
  • [05/08/2025] DLC pipework update.
  • [29/07/2025] Transformer repair update.
  • [25/06/2025] Full maintenance complete.
  • [25/06/2025] Maintenance update.
  • [24/07/2025] Maintenance update.
  • [23/07/2025] Maintenance update.
  • [22/07/2025] Maintenance update post network blackout.
  • [21/07/2025] Maintenance start. Per service status update.
  • [18/07/2025] (17:04) IRIS/Gaia shutdown on July 20th clarified.
  • [18/07/2025] Information added about July 21st-25th maintenance.
  • [17/07/2025] Transformer repair work confirmed for July 29th.
  • [11/07/2025] July 21st-25th rescheduled cooling and network maintenance confirmed. September 18th date for rescheduled power sequencing confirmed.
  • [04/07/2025] Mark July 8-10 as cancelled.
  • [27/06/2025] Update re July 8-10 and subsequent timeline.
  • [24/06/2025] Update post June 24th events.
  • [23/06/2025] Updated dates and details for work on July 8-10th.
  • [17/06/2025] Warm weather update, transformer repair for 24th June added and July full maintenance update.
  • [10/06/2025] Version string and change log added.
  • [23/05/2025] Page created.
[1]This refers to the racks in rows C-F in data hall 1. These contain elements of CSD3, SRCP, Arcus and storage, so parts of these services may be affected during these phases of the work.