Dr. Olga Zhelenkova
Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhnii Arkhyz, Russia
(pdf of presentation is available here)
The data of experiments require archiving and reliable storage with accessibility and semantic reenterability. In the SAO RAS in the early 80-ies for these purposes a digital archive of radio observations was created. Then with the introduction of CCD cameras into observations in the late 80s we started to develop a data bank, which united the different digital collections. Latter we realized an archiving system with a search information system. To date, the archive capacity is 1.5 TB, also there are 0.5 million files and 1 million records in the database. The system supports free web access to 16 local archives with digital collections of different devices used, or been used in the telescopes of the observatory. Two servers with PostgreSQL database each support the system. Each server data storage area has a similar structure and content. One server supports and contains the working version of the system, the second one supports the test version, with which we carry out and test all the new developments. The system was developed so that it was possible to add a new collection. There is a possibility of hosting other Russian telescope archives. In order to provide additional reliability of information keeping, archival data is still stored on the optical CD/DVD disks. There is no doubt in the need for long-term storage of astronomical data. As example, the sky survey conducted by the RATAN-600 in 1980, with the results of which it was obtained the first restriction on the value of CMB fluctuations, then these observations we used to study the variability of the radio sources and transients search. The life cycle of modern digital carriers is usually 5-10 years, that also applies to the read-write hardware and software. So while changing magnetic, data and streamer tapes to hard drives some of our collections, fortunately minor could not be read from the carriers for these reasons. A timely migration of digital files on the modern carriers is required to ensure long-term storage of data. Recently, a new storage media is appeared. It is the M-disc designed for long-term storage of unchanging data (http://millenniata.com). We plan to make migration of the archived data to the M-discs. The manufacturer promises shelf life of the disks up to 100 years but it is a predicted term. Nevertheless, it is not possible to completely abandon from external carriers for long-term data storage and fully transfer the information to the database only. Other way of supporting long-term preservation is based on a multi-tiers hardware architecture and special software systems like iRODS (integrated Rule-Oriented Data System, http://irods.org). It is an open source data management software used by research organizations. iRODS virtualizes data storage resources, so users can take control of their data, regardless of where and on what device the data is stored. We are going to start works for migration our data into the new environment based on iRODS.
Created / Updated: 30 September 2016 / 7 August 2018