Abstract: Aiming at the performance difference of real storage devices in object-based storage system，a 2-D tiles pair of base vectors twice mapping declustering method based on virtual device is proposed.Firstly，a group of virtual devices which have same storage performance and non-limited capacity is constructed，then the tiles are distributed into M virtual devices according to the distribution model of 2-D tiles pair of base vectors.Secondly，the tiles are equably mapped in M virtual devices into M equidistant intervals in [0，1） using pseudo-random number generator.Finally，[0，1） is divided into M intervals according to the tiles distribution percentage of every real device，and the tiles in each interval are distributed in the corresponding real device.

Key words: 2-D tiles, pair of base vectors, virtual device, object-based storage

摘要： 针对基于对象存储系统中各个存储设备的性能差异，提出了一种二维瓦片矢量基对二次映射分布方法。首先，构建一组性能相同、容量无限的虚拟设备，并根据矢量基对分布模板将二维瓦片分布到M个虚拟设备中；然后，通过伪随机数发生器将M个虚拟设备中的瓦片均匀映射到[0，1）区间的M个等分区间；最后，根据真实设备的瓦片分布百分比将[0，1）区间划分成M个区间，并将映射到各个区间的二维瓦片分布到对应的真实设备中。

关键词: 二维瓦片, 矢量基对, 虚拟设备, 基于对象存储