The disclosure provides an OSD (object-based storage device)
selection method, a data writing method and device and a storage
system. The OSD
selection method comprises: in PG (placement group) addressing mapping phase in Ceph, determining from a first available OSD
list, an OSD group corresponding to the current PG according to CRUSH
algorithm; setting an OSD, having highest reading-writing speed, in the OSD group as a master OSD, and determining the other OSDs in the OSD group expect for the master OSD as slave OSDs; determining from a second available OSD
list, a temporary OSD correspondingto the current PG according to the CRUSH
algorithm, wherein the temporary OSD is one OSD having highest reading-writing speed in the second available OSD
list and is different from those in the OSD group, and the first available OSD list is a subset to the second available OSD list. By using the OSD (object-based storage device)
selection method, the data writing method and device and the storagesystem, data reading-writing rate can be increased.