2. Belle II experiment
Requirement of data handling system
Belle II Metadata service system
Data Cache system at Belle II experiment
Summary

3. 1. Belle II experiment Accelerator update ⇒ Super KEKB
Circulation: 3km
Beam Energy Asymmetric:
7.0(e-) X 4.0(e+) → GeV (CM)

4. 1. Belle II experiment Belle II Belle Belle Content Belle II 1999~2010
Time Schedule
2014~
1 ab-1
Luminosity
50 ab-1
1 Billion
BBbar events
50 Billion
CP measurement
Goal
New Physics
Belle II
Belle

5. 2. Requirement of data handling system @ Belle II experiment
We need MC(at least data X 3)/data for an analysis.
It takes 20 days for skimming using Belle data (2.4 billion events).
We suppose 50 times larger data of Belle II than that of Belle.
If we suppose that the technology be improved two times,
then we can estimate 500 days for Belle II pre-selection works.
We suggest the meta system of the event-level and
Data Cache system.
If we have the good information at metadata system,
then we can reduce the CPU times for pre-selection.
ex) Fox-Wolfram momentum, number of tracks and so on

6. To construct the DH system for Belle II experiment3.
Belle II Metadata service system
To construct the DH system for Belle II experiment
To improve the scalability and performance
To run based on grid farm
⇒ AMGA (Arda Metadata Catalog for Grid Application)
Data Cache
AMGA

7. 4. Data Cache system at Belle II experiment
Every pre-selection data is stored in mDST (mini Data Structure
Table) format.
However, these files occupy so much disk space. Then, we
start suffering from the lack of disk space.
Basically, Index file has information of the Run period / Run number
/ Event number of events which have been passed the selection.
So, the size of file can be reduced very much.
However, the current system has a demerit because it can be used
only at local network, not on Grid.
Therefore, we have developed the Data Cache system which works
on Grid.

8. 4.
Data Cache system at Belle II experiment
* SE (Storage Element)

9. 4. Data Cache system at Belle II experiment
We make the simple data tool
which is not based on database.

10. 4. Data Cache system at Belle II experiment
The estimation of Data Cache
We select the sample data for the estimation of Data Cache.
We obtain the metadata from event-level searching.
The results show same between Belle and Belle II.
We reduce the size of index file.

11. 4.
Data Cache system at Belle II experiment
(Byte)

12. 5. Summary Constructed the searching service system
Designed and developed the Data Cache system
Connected the Data Cache system and searching system
Estimated the Data Cache system
Found and applied Grid system