Chapter 6. Storage

LIO kernel Target Subsystem

Red Hat Enterprise Linux 7.0 Beta uses the LIO kernel target subsystem, which is the standard open source SCSI target for block storage, for all of the following storage fabrics: FCoE, iSCSI, iSER (Mellanox InfiniBand), and SRP (Mellanox InfiniBand).
Red Hat Enterprise Linux 6 uses tgtd, the SCSI Target Daemon, for iSCSI target support, and only uses LIO, the Linux kernel target, for Fibre-Channel over Ethernet (FCoE) targets via the fcoe-target-utils package.
The targetcli shell provides the general management platform for the LIO Linux SCSI target.

Fast Block Devices Caching Slower Block Devices

The ability to have fast block devices act as a cache for slower block devices is introduced as a Technology Preview in Red Hat Enterprise Linux 7.0 Beta. This feature allows a PCIe SSD device to act as a cache for direct-attached storage (DAS) or storage area network (SAN) storage, which improves file system performance.