最近在调试Heartbeat的时候，从代码中发现，Linux 集成到内核下的iSCSI target ，已经从TGT变更为LIO。 一直奇怪TGT 的版本怎么没什么更新，原来是技术原因没落了。2010年底，LIO 项目获选成为新的内核态的 SCSI target，取代原有的用户态的 STGT 项目。并集成到2.6.38以后的Linux 内核中
The SCSI Target Framework (STGT/TGT) was the standard before linux 2.6.38.
The current standard is the LIO target.
The iSCSI Enterprise Target (IET) is an old implementation and SCSI Target Subsystem (SCST) is the successor of IET and was a possible candidate for kernel inclusion before the decision fell for LIO.
At the end of 2010, the LIO
project was chosen to replace STGT as the in-kernel SCSI target
implementation. There were two main contenders (LIO and SCST) which tried
to get their code into the Linux kernel tree. This article will compare
the two projects and try to describe what these implementations have to offer.---LIO
has been the default block storage target from CentOS version 6.2, released on 12/20/2012.