The Research And Implementation Of ISCSI And FC Link Integration In Storage System

As the increase of enterprise storage requirement, traditional SCSI local storage model has been gradually replaced by SAN model which has great storage capacity and high transport speed. The familiar SCSI transports iSCSI and FC have their advantage and disadvantage respectively, so there is a trend that they should be integrated into one storage system.On the basis of server-level integration storage system, studied the feasibility of different links integration in storage system, brought forward a three-level architecture to implement the integration on the storage server: Uniform SCSI initiator subsystem supports the different links to the low level storage devices, uniform SCSI target subsystem supports the different links to the upper level application server, and the middle level storage virtualization subsystem manages the mapping between low level device storage space and upper level application server storage space. In the SCSI target subsystem, separated the device independent work from the target module and form the universal uniform module. This module manages the storage requests together. Studied and compared the user space and kernel space implementation in Linux, and chose the latter way. In virtualization subsystem adopts the simple convenient LVM as the basic, using the uniform speciality of the Linux block device file operation, add a virtualized disk operation module in target module to cooperate with the uniform SCSI target middle level to access the LVM logical volume.After system feasibility and performance test, this link integration scheme is feasible, can support iSCSI, FC link simultaneously, and can be managed uniformly. The storage system which adopts this scheme has the high storage performance which meets the general user requirement. But there could be bottle-nack and some data consistency problems in integration server. It should be improved.