COMPUTER SYSTEM AND CONTROL METHOD FOR THE SAME
A computer system with a plurality of storage systems connected to each other via a network, each storage system including a virtual machine whose data is stored in hierarchized storage areas. When a virtual machine of a first storage system is migrated from the first storage system to a second storage system, the second storage system stores data of the virtual machine of the first storage system as well as data of its own virtual machine, in the hierarchized storage areas in the second storage system.
1 . A computer system with a plurality of storage systems coupled to each other via a network, the computer system comprising:
a first storage system; and
a second storage system;
wherein the first storage system includes a first computer for operating a first virtual machine and stores data of the first virtual machine in a first memory unit that is hierarchized;
wherein the second storage system includes a second computer for operating a second virtual machine and stores data of the second virtual machine in a second memory unit that is hierarchized; and
wherein when the first computer migrates the first virtual machine to the second computer, the second computer stores data of the first virtual machine and data of the second virtual machine in the second memory unit.
2 . The computer system according to claim 1 , wherein a shared storage unit shared by the first storage system and the second storage system is connected to the network;
wherein the first storage system has a first dedicated storage unit for storing data of the first virtual machine for exclusive use and the first memory unit is configured by hierarchizing the first dedicated storage unit and the shared storage unit; and
wherein the second storage system has a second dedicated storage unit for storing data of the second virtual machine for exclusive use and the second memory unit is configured by hierarchizing the second dedicated storage unit and the shared storage unit.
3 . The computer system according to claim 2 , wherein the first computer has a first logical volume for access to the first virtual machine;
wherein the second computer has a second logical volume for access to the second virtual machine; and
wherein when the first computer migrates the first virtual machine to the second computer, it migrates the first logical volume to the second computer.
4 . The computer system according to claim 2 , wherein each of the first dedicated storage unit and the second dedicated storage unit includes a Tier 0 storage device, and
the shared storage unit has a Tier 2 storage device.
5 . The computer system according to claim 3 , wherein the first logical volume has a first virtual volume and a storage area in the first memory unit is allocated to the first virtual volume, and
the second logical volume has a second virtual volume and a storage area in the second memory unit is allocated to the second virtual volume.
6 . The computer system according to claim 5 , wherein the second computer changes a form of allocation of the storage area in the first memory unit to the first virtual volume according to frequency of access to the first logical volume in the first virtual machine.
7 . The computer system according to claim 5 , wherein the second computer changes a form of allocation of the storage area in the second memory unit to the second virtual volume according to frequency of access to the second logical volume in the second virtual machine.
8 . The computer system according to claim 5 , wherein the second computer changes a form of allocation of the storage area in the first memory unit to the first virtual volume according to frequency of access to the first logical volume in the first virtual machine; and
the second computer changes a form of allocation of the storage area in the second memory unit to the second virtual volume according to frequency of access to the second logical volume in the second virtual machine.
9 . The computer system according to claim 3 , wherein the second computer migrates data of the second dedicated storage unit to the shared storage unit; and
migrates data of the first dedicated storage unit to the second dedicated storage unit.
10 . The computer system according to claim 3 , wherein the second computer compares frequency of access to data of the second dedicated storage unit with frequency of access to data of the first dedicated storage unit; and
if the former access frequency is lower than the latter access frequency, the second computer migrates the data of the second dedicated storage unit to the shared storage unit and migrates the data of the first dedicated storage unit to the second dedicated storage unit.
11 . The computer system according to claim 10 , wherein the second computer migrates data which has not been migrated to the shared storage unit, from among the data of the first dedicated storage unit, to the shared storage unit.
12 . The computer system according to claim 11 , wherein after migration of the first virtual machine and the first logical volume to the second computer and before migration of data of the first virtual machine to the second computer, the second computer accesses the first computer based on access by the first virtual machine to the first logical volume; and
wherein the first computer reads target data from the first dedicated storage unit based on access by the second computer and sends this data to the second computer.
13 . A data storage control method for a computer system with a plurality of storage systems connected to each other via a network, each of the plurality of storage systems having a virtual machine whose data is stored in hierarchized storage areas,
wherein when a virtual machine of a first storage system is migrated from the first storage system to a second storage system, the second storage system stores data of the virtual machine of the first storage system as well as data of its own virtual machine in the hierarchized storage areas in the second storage system.