Patent ID: 9639277
Date: 2017-05-02
CPC Classifications: G06F

Claim:
1. A system comprising: a host system; and a plurality of storage systems providing a distributed virtual volume to the host system; wherein each of the plurality of storage systems is configured to manage a volume constituting a portion of the distributed virtual volume; wherein the host system is configured to manage hit/miss information regarding IO (Input/Output) hit and IO miss of IO requests issued to destinations for accessing the distributed virtual volume, and wherein the host system is configured to: issue a first IO request to one of destinations for accessing a first portion of the distributed virtual volume on the basis of the hit/miss information; update the hit/miss information on the basis of IO hit or IO miss of the first IO request; and issue a second IO request to another one of the destinations for accessing the first portion of the distributed virtual volume on the basis of the updated hit/miss information, in case that IO miss of the first IO request occurred; wherein the destinations for accessing the distributed virtual volume are target ports of the plurality of storage systems for accessing each volume constituting a portion of the distributed virtual volume; wherein each volume stores target port group information including the target ports and access statuses of the target ports to control IO destinations of the IO requests; and wherein the access status of all target ports associated with a target port group is identical and is changed simultaneously.