1. Scientific computing @ LNGS: users point of view
Alessandro Razeto
LNGS 26/2/14

2. LNGS is not a normal INFN Unit
An international reality
The most international lab of INFN
With international experiments
Some of which have minority Italian collaboration
On the way for an ERIC
European Research Infrastructure Consortium
LNGS is a small CERN and deserve the same dignity
We need to maintain LNGS international role for scientific computing too
And we want to be the reference for the scientific results of the experiments

3. Users In a typical INFN Unit users are: In LNGS there are also:
Researchers
Associati (= Professors and researchers from associated Universities)
Graduate students
Post Docs
In LNGS there are also:
L’Aquila group
GSSI students
Foreigner researchers
Foreigner students
Shifters
As result the scientific community at LNGS rounds up to 100 users
While the local scientific division has only 20 researchers + associati
We can not consider the LNGS as a small unit

4. INFN Policy for Computing
CNAF is the computing center for INFN experiments
Better economy
Bigger orders -> lower prices
All man power in a single place
Scale the shared resources
Experiments can profit from CPU unused by others
Italian groups of LNGS experiments should use CNAF
And LNGS users?

5. INFN Policy & LNGS experiments
Does INFN policy about computer fit the experiments?
Weakly
In the past years several international experiment installed in LNGS some computing resources
INFN risks to loose control on scientific computing at LNGS
A compromise has to be found
That allows international collaborations to refer directly to LNGS for their on-site computing requirements
That allows integration with the INFN general picture

6. INFN Policy & LNGS users
Given for granted that CNAF is the place for big processing
Where can LNGS users develop algorithms and perform interactive analysis?
LNGS researchers do not coincide with their experiments
Where can users analyze their R&D or their simulations?
CNAF is probably not the solution for these necessities
A local infrastructure is needed

7. Why do experiments install CPU in LNGS?
The lifecycle of an LNGS experiment is quite different from an LHC one
Typically people building the detectors are the same that later develop the analysis
Typically the computing infrastructures at LNGS spring from tiny systems where the users started early development
Often realized during R&D or the installation of the detector
Typically the burden to move the programs to CNAF requires resources not easily allocable
In any case it is clear that there is a common behaviour
We should embrace this pattern and drive it to a direction compatible with INFN policies
A closure from INFN could aggravate this pattern pushing future experiments to buy computing resources on CF (or on foreigner budget)

8. How to continue
According to users

9. Proposal
We need a computing cluster in LNGS that is designed integrated with CNAF
This can be done with the CLOUD

10. Underground Clouds
Cloud techniques allow to have the same interface for both LNGS and CNAF processes
In this way users and new experiments at LNGS are on the fast lane for doing massive computing at CNAF
This system
Allows LNGS to keep some scientific independence about computing in view of the ERIC
Keeps the LNGS as the reference center for scientific computing for international experiments
Allows users to develop algorithms and to perform interactive analysis at LNGS
U-Lite could be the core from where to start such integration

11. Resources We are asking for small resources
CPU -> 5 kHS06 to start + 1 kHS06/year
About 3 kHS06 already in LNGS
20 k€ + 10 k€/year
Tape writer dedicated raw data
Sized for 500 TB/year
20 k€
Maintenance
15 k€/year
Tapes and Disks charged to the experiment

12. Local Data
Almost all labs around the world keep a local copy of raw data
CERN has 2 copies of raw-data
FNAL policy keeps the primary copy of raw data (up to 3 year after the end of the experiment)
We propose the following policy in agreement with the experiments
A copy on disks of all rawdata produced at LNGS is kept locally
Not a new policy
Past and current experiments are keeping data in LNGS

13. Conclusions