Patent ID: 9405478
Filing Date: 2016-08-02
CPC Classification: G06F

Claim Text:
1. A storage control method for a storage apparatus including a storage controller and a plurality of nonvolatile semiconductor storage units, each including a plurality of nonvolatile semiconductor memory chips, each of the plurality of nonvolatile semiconductor memory chips including a plurality of blocks, the method comprising the steps of: managing life length information based on at least erasing frequency of the plurality of blocks and providing logical storage regions corresponding to the plurality of nonvolatile semiconductor memory chips; writing data to a nonvolatile semiconductor storage unit that is a basis of a logical storage region of a write destination of a plurality of logical storage regions; sending a request to each of the nonvolatile semiconductor storage units for acquiring the life length information; sending the life length information to the storage controller in response to the request; identifying, based on the life length information, a first nonvolatile semiconductor storage unit, and a second nonvolatile semiconductor storage unit that has a remaining length of life longer than a remaining length of life of the first nonvolatile semiconductor storage unit; transferring data from a first logical storage region of the first nonvolatile semiconductor storage unit to a second logical storage region of the second nonvolatile semiconductor storage unit; determining whether the remaining life length of a particular nonvolatile semiconductor storage unit is shorter than a remaining guarantee period; moving, when it is determined that the remaining life length of the particular nonvolatile semiconductor storage unit is shorter than the remaining guarantee period, data to a hard disk drive (HDD) that is free of an upper limit of rewriting, wherein: the plurality of nonvolatile semiconductor storage units configure a plurality of nonvolatile semiconductor storage RAID groups, a plurality of HDDs configure a HDD RAID group, and data is moved between the nonvolatile semiconductor storage RAID groups and the HDD RAID group in a unit of an extent; determining whether the remaining life length of a first nonvolatile semiconductor storage RAID group is shorter than a remaining guarantee period of the first nonvolatile semiconductor storage RAID group; moving, when it is determined that the remaining life length of the first nonvolatile semiconductor storage RAID group is shorter than the remaining guarantee period of the first nonvolatile semiconductor storage RAID group, data to a second nonvolatile semiconductor storage RAID group having a remaining life length that is longer than a remaining guarantee period of the second nonvolatile semiconductor storage RAID group; determining whether the remaining life length of all of the nonvolatile semiconductor storage RAID groups is shorter than a remaining guarantee period of all of the nonvolatile semiconductor storage RAID groups; and moving, when it is determined that the remaining life length of all of the nonvolatile semiconductor storage RAID groups is shorter than the remaining guarantee period of all of the nonvolatile semiconductor storage RAID groups, data to the HDD RAID group.