  The New Vacuum Solar Telescope (NVST) is a 1-m solar telescope that aims to
observe the fine structures in both the photosphere and the chromosphere of the
Sun. The observational data acquired simultaneously from one channel for the
chromosphere and two channels for the photosphere bring great challenges to the
data storage of NVST. The multi-channel instruments of NVST, including
scientific cameras and multi-band spectrometers, generate at least 3 terabytes
data per day and require high access performance while storing massive
short-exposure images. It is worth studying and implementing a storage system
for NVST which would balance the data availability, access performance and the
cost of development. In this paper, we build a distributed data storage system
(DDSS) for NVST and then deeply evaluate the availability of real-time data
storage on a distributed computing environment. The experimental results show
that two factors, i.e., the number of concurrent read/write and the file size,
are critically important for improving the performance of data access on a
distributed environment. Referring to these two factors, three strategies for
storing FITS files are presented and implemented to ensure the access
performance of the DDSS under conditions of multi-host write and read
simultaneously. The real applications of the DDSS proves that the system is
capable of meeting the requirements of NVST real-time high performance
observational data storage. Our study on the DDSS is the first attempt for
modern astronomical telescope systems to store real-time observational data on
a low-cost distributed system. The research results and corresponding
techniques of the DDSS provide a new option for designing real-time massive
astronomical data storage system and will be a reference for future
astronomical data storage.
