| 摘要 |
<p>Data migration is made to be performed in short time without actual data move and independent from the capacity of a magnetic disk volume (10a-10d in Fig. 1). As viewed from an upper hierarchical system, "new physical drive installation or addition" (80-15,---- 80-45 in Fig. 8) can be performed easily, rapidly and safely. If a physical address is to be changed after a host generates or updates data in a magnetic disk volume (80-11, ---- 80-14 in Fig. 8), a service processor (250) is made to change only a correspondence between physical and logical addresses (Fig. 3). The physical address can therefore be changed by retaining the data written in a magnetic disk. Accordingly, if there is an idle area in a physical drive (Fig. 8), as viewed from an upper hierarchical system, "physical drive installation or addition" can be performed easily.</p> |
