NEWS!
DHS move finished on 11 November
Updated recommended user action for Metview
DHS Move start on 8 Sept, see DHS move in detail
Service disruption during dry-run system session 28 June - 5 July
- Last chance to check whether your MARS/ECFS activity will continue to run during the actual DHS Move
Transition plan
The Data Handling System (DHS), providing the MARS and ECFS services, needs to be moved to Bologna before the new Atos HPCF will produce an increased archive load. A detailed migration timeline is shown in the transition plan below where all events are relative to day D, the day when the MARS and ECFS service will stop accessing the Main-DHS-Reading. Instead the MARS and ECFS service will be provided by a temporary DHS which has been pre-filled with data necessary to continue operational and time-critical activities at ECMWF, with the aim to minimise the impact of the DHS move. After 6 days we will start filling the new Main-DHS-Blank with the data from the Temporary-DHS-prod and from the Main-DHS-Reading. At the end of the DHS-Move, expected to take 5-6 weeks, a new main DHS will become operational in Bologna. In preparation of the DHS move we will conduct a number of dry-runs during which the access to the main DHS in Reading will be blocked. The purpose of the dry runs is to verify that the Temporary-DHS does contain all essential data necessary to continue all critical activities during the move. A longer dry-run, lasting 5-7 days, expected to happen at least 4 weeks before the move, will help to establish the exact date of day D.
Main service disruptions
The table below gives an indication of disruptions to the MARS and ECFS service foreseen as part of the DHS-Move. Dates are subject to change depending on experience with preceding dry-runs.
| Event | Start Date/Time | Duration | Impact |
|---|---|---|---|
| Dry-run 1 | 5 April 2022, 8 UTC | 10 hours | access limited to available data, see DHS move dry-run for more details |
| Dry-run 2 | 26 April 2022, 10 UTC | 48 hours | access limited to available data, see DHS move dry-run for more details |
| Reduced service dry-run | 28 June | 7 days | access limited to available data, see DHS move dry-run for more details |
| DHS Move | 8 September | 5-6 weeks | access limited to available data, all archive content becoming gradually available again during the move, see DHS move in detail |
Summary of impact by user group
This table highlights how specific user groups will be affected by the DHS-Move. See further below for more details on the availability of specific data.
| User group | Impact |
|---|---|
| Member State User (fully registered computer user) | mars-client/WebAPI/ECFS - Access limited to available data |
| Web User (registered by MS) | WebAPI - Access limited to available data |
| Commercial and research user (maxch*, comarc*, resarc*, nm*) | WebAPI - No access to historical operational data and IFS research experiments |
| Public users | WebAPI - No access to public datasets (TIGGE, S2S, etc.) |
Commercial users (comarc_*) with a valid licence during the outage will have the equivalent length of the outage added to their existing contract length.
Users may also opt to terminate their licence with 4 weeks notice.
Impact to MARS service
The following list of available data, not expected to be impacted during dry-runs and the DHS-Move, will be updated in light of further migration progress:
- Recent output (~ one month) from operational production systems: All products listed in the Catalogue of ECMWF real-time products, ERA5T (near real-time), ADS data on disk or from external providers, CDS data on disk or from external providers
Observations, analysis input, tropical cyclones for the entire period
ERA5 data required as initial conditions for the operational hindcasts (20 years for the relevant weeks)
The following services are not expected to be impacted by dry-runs and the DHS-Move:
- Archiving into MARS
- MS Time-critical suites
- Atos HPC testing
Any data not listed as available during dry-runs and the DHS-Move will not be accessible, in particular:
- Public datasets
- IFS Research experiments
- Historical operational data
- ADS datasets served from MARS tapes
- CDS datasets served from MARS tapes
Impact to ECFS service
During dry-runs and the DHS-Move ECFS will be impacted as follows:
The following list of available data, not expected to be impacted during dry-runs and the DHS-Move, will be updated in light of further migration progress:
- Recent output (~ one month) from operational production systems
- Observations
- Any data written during dry-runs and DHS-Move
The following services are not expected to be impacted by dry-runs and the DHS-Move:
- Writing into ECFS
- All 'metadata' operations (listing, renames, moves, deletions, changing ownership/permissions).
- MS Time-critical suites
- Atos HPC testing
The following services/data will not be available during dry-runs and the DHS-Move:
- Any data not listed as available above, in particular IFS Research experiment data and historical operational data. For data offline the first character in the output of the 'els -l' command will be replaced with 'o'.
The commands ecp, emv and ecat accessing data which are not available will fail with a 'Data Offline' error without retrying.
Recommended user action
- Users of MARS and ECFS are urged to check if and how their work might be affected by the DHS-Move and plan accordingly.
- Major changes to production processes etc. are best avoided during this period. For some activities the best course of action might be to avoid the migration period entirely...
- ECMWF computer users missing access to data for any critical activity during the DHS-Move should contact us at their earliest convenience with their requirements via the ECMWF Support Portal.
- Since the start of the DHS Move users need to use the modules metview/new (on Reading systems) and ecmwf-toolbox/new (on Bologna systems) to have a working MARS client inside Metview.