Current System Load
The plot below shows the status of the CPU nodes on the current Cirrus service for the past day.
A description of each of the status types is provided below the plot.
CPU
- alloc: Nodes running user jobs
- idle: Nodes available for user jobs
- resv: Nodes in reservation and not available for standard user jobs
- down, drain, maint, drng, comp: Nodes unavailable for user jobs
- mix: Nodes in multiple states
Service Alerts
| Status | Start | End | Scope | Impact | Reason |
|---|---|---|---|---|---|
| Planned | 2026-06-09 10:00 | 2026-06-26 18:00 | Full system | Possible interruption to login access and compute node availability | Work to expand Cirrus to 640 compute nodes |
Recently Resolved Service Alerts
This table lists the last five resolved service alerts A full list of historical resolved service alerts is available.
| Status | Start | End | Scope | Impact | Reason |
|---|---|---|---|---|---|
| Resolved | 2026-05-29 11:00 | 2026-05-29 12:15 | Compute nodes | No new jobs can start on Cirrus. Running jobs continue as usual. | Issues with cooling infrastructure |
| Complete | 2026-05-18 09:00 | 2026-05-20 18:00 | ceph Work Storage system | Possible slower than normal responses whilst the update works take place | Maintenance on the ceph /work storage system |
| Resolved | 2026-05-01 13:20 | 2026-05-01 14:05 | Cooling | New work has been prevented from starting to reduce load on the cooling system | Issues with cooling infrastructure |
| Resolved | 2026-04-30 15:55 | 2026-04-30 18:00 | Cooling | New work has been prevented from starting to reduce load on the cooling system | Issues with cooling infrastructure |
| Resolved | 2026-04-30 10:30 | 2026-04-30 12:30 | Login access | No login access to Cirrus | An emerging security threat |
Service Maintenance Sessions
We keep maintenance downtime to a minimum on the service but do occasionally need to perform essential work on the system. Maintenance sessions are used to ensure that:
- software versions are kept up to date;
- firmware levels on HPE and third-party peripheral equipment are kept up to date; essential security patches are applied;
- failed/suspect hardware can be replaced;
- new software can be installed; periodic essential maintenance on HPE electrical and mechanical support equipment (refrigeration systems, air blowers and power distribution units) can be undertaken safely.
Additional maintenance sessions can be scheduled for major hardware or software updates; major upgrades to facility plant and infrastructure; acceptance testing following major service upgrades and statutory electrical testing.
| Status | Start | End | Scope | Impact | Reason |
|---|---|---|---|---|---|
| Planned | 2026-06-22 08:30 | 2026-06-24 13:00 | Compute nodes | All Cirrus compute nodes will be unavailable. Login access will remain available at risk. | Acceptance testing of expanded Cirrus system - dates may change depending on installation progress |
| Planned | 2026-06-02 08:30 | 2026-06-09 10:00 | Compute nodes | All Cirrus compute nodes will be unavailable. Login access will remain available at risk. | Work to expand Cirrus to 640 compute nodes |
A list of all previous maintenance sessions.