ECDF: Edinburgh Compute and Data Facilities
'Eddie' Compute Cluster
Eddie is a compute cluster run by the ECDF team (a part of IS). It consists of a large number (~2000) of cores connected by fast networking (including infiniband for a subset of nodes). More information is available on the ECDF wiki page: www.wiki.ed.ac.uk/display/ecdfwiki/Home.
Getting Access to Eddie
Just fill in the ECDF compute cluster registration form (registration.ecdf.ed.ac.uk/eddiereg/). As long as your details in the University's identity management services are correct, the ECDF team will know that you are an Engineering user and give you an account. That's it.
Using Free Compute Time on Eddie
The school of Engineering has paid for a share of time on Eddie. This amounts to 10% of the total CPU time, enforced over a window of a few weeks so that jobs can use more than 200 nodes for short periods of time without falling foul of the scheduler. Of that 10%, 15% is allotted to free use within the School. As soon as you have an account you can use Eddie and until you pay for some guaranteed share (see More About Shares below) you will be competing with everyone else for your share of that 15%.
You should use your part of the 15% free share of Eddie to investigate Eddie's capabilities and suitability for your task, to develop your code to the point where it is ready for larger scale use, or for small projects. Once you are ready to run some heavy duty work, you should consider paying for access to the other 85% of Engineering's share.
Using Paid For Compute Time on Eddie
85% of Engineering's share of Eddie is set aside for those who are paying for access. The charge for this is £40 per 1% guaranteed share per month. The concept of 'guaranteed share' is explained more fully in More About Shares.
To pay for some guaranteed share on Eddie:
- Use the School's requisition system
- Set the supplier to 'ECDF'
- Specify how many units of 1% guaranteed share you would like @ £40
- Specify which months (e.g. 5% share for July and August = £40*5*2=£400)
- If you have more than one ECDF project specify which project the share applies to
Once request is raised the finance team will forward the information to ECDF who will adjust project shares accordingly.
More About Shares
SPECfp, core equivalents
Currently Engineering has 4950 SPECfp allocated to it which is equivalent to 550
2007 cores. A 1 per cent share is thus 49.5 Specfp or 5.5 2007 cores.
Guaranteed Share and the Scheduler
Eddie's job scheduler uses a concept called 'guaranteed share' to ensure fair use of the system. The system guarantees that users (actually projects) get at least their guaranteed share of CPU time when averaged over a given time window. That window is two weeks wide with a decaying tail. Roughly speaking the whole corresponds to a month, which is why we are reselling guaranteed share on a monthly basis.
Note that, if the system is not fully used, you can use more than your guaranteed share, but you will never end up with less as long as you provide the system with work to do during that time. If you do pay for guaranteed share you should therefore ensure that you have plenty of work in the queue during the time period for which you are paying. We would recommend that you use free share to make sure your code is working and pay for guaranteed share once you are ready.