iSCSI is an emerging transport protocol for transmitting SCSI storage I/O commands and data blocks over TCP/IP networks. It allows storage devices to be shared by multiple network hosts. A fundamental problem is how to enable consistent and efficient data sharing in iSCSI-based environments. In this paper, we propose a suite of data sharing schemes for iSCSI-based file systems and use ext2 as an example for implementation. Finally, we use simulations to verify the correctness of our designs and to study the performances. 1