  Astronomical observation data require long-term preservation, and the rapid
accumulation of observation data makes it necessary to consider the cost of
long-term archive storage. In addition to low-speed disk-based online storage,
optical disk or tape-based offline storage can be used to save costs. However,
for astronomical research that requires historical data (particularly
time-domain astronomy), the performance and energy consumption of
data-accessing techniques cause problems because the requested data (which are
organized according to observation time) may be located across multiple storage
devices. In this study, we design and develop a tool referred to as AstroLayout
to redistribute the observation data using spatial aggregation. The core
algorithm uses graph partitioning to generate an optimized data placement
according to the original observation data statistics and the target storage
system. For the given observation data, AstroLayout can copy the long-term
archive in the target storage system in accordance with this placement. An
efficiency evaluation shows that AstroLayout can reduce the number of devices
activated when responding to data-access requests in time-domain astronomy
research. In addition to improving the performance of data-accessing
techniques, AstroLayout can also reduce the storage systems power consumption.
For enhanced adaptability, it supports storage systems of any media, including
optical disks, tapes, and hard disks.
