A Ceph S3 Object Data Store for HEP Smith, Nick; Jayatilaka, Bo; Mason, David ...
EPJ Web of Conferences,
2024, Letnik:
295
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In CMS, data access and management is organized around the data tier model: a static definition of what subset of event information is available in a particular dataset, realized as a collection of ...files. We present a novel data management model that obviates the need for data tiers by exploding files into individual event data product objects. The objects are stored and retrieved through Ceph S3 technology, with a layout designed to minimize data and metadata volume while maximizing data processing parallelism. We demonstrate that this object data format shows promise in reducing total storage requirements while allowing more flexible data access patterns. Performance benchmarks of a prototype data processing framework using this object data format and a test Ceph cluster are presented, showing good scaling behavior in a distributed processing task.
The universe contains many extremely energetic astrophysical sources that emit particles on timescales from fractions of a second to thousands of years. Studying these sources through gamma-ray and ...multi-messenger astronomy may help to reveal the answers to several remaining fundamental questions in physics. The High Altitude Water Cherenkov (HAWC) gamma-ray observatory, an extensive air shower array, is well-suited to perform transient searches due to its large field of view and high duty cycle. In this work, a catalog search of all very-high-energy gamma-ray sources in HAWC's field of view is conducted, revealing a total of 65 sources. Then a search for evaporating primordial black holes is performed. None are detected, so upper limits are set on their burst rate density. Finally, the IceCube neutrino observatory is introduced in order to perform a multi-messenger search for flaring gamma rays and neutrinos originating from the same point in the sky. None are detected, so upper limits are placed on the rate density and total energy of sources that produce both gamma rays and neutrinos. Performing these searches contributes to the understanding of the origins of cosmic rays and how astrophysical sources accelerate their particles to the high energies that are observed on Earth.
Primordial Black Holes (PBHs) are black holes that may have been created by density fluctuations in the early Universe and could be as massive as supermassive black holes or as small as the Planck ...scale. It is believed that a black hole has a temperature inversely proportional to its mass and will thermally emit all species of fundamental particles via Hawking Radiation. PBHs with initial masses of ~5e14 g (approximately one gigaton) should be expiring today with bursts of high-energy gamma radiation in the GeV – TeV energy range. The High Altitude Water Cherenkov (HAWC) Observatory is sensitive to particles with energies of 300 GeV – 100 TeV, which corresponds to the high end of the PBH burst spectrum. With its large instantaneous field of view of ~2 sr and a duty cycle above 95%, the HAWC Observatory is well suited to perform an all-sky search for PBH bursts. We conducted a search on 959 days of gamma-ray data from HAWC by optimizing a previous gamma-ray burst transient search to the PBH burst energy spectrum, and placed the strongest upper limits on the local PBH burst rate density at the 99% confidence level.
We present a novel data format design that obviates the need for data tiers by storing individual event data products in column objects. The objects are stored and retrieved through Ceph S3 ...technology, with a layout designed to minimize metadata volume and maximize data processing parallelism. Performance benchmarks of data storage and retrieval are presented.
