A SCSI3 Persistent Reservation Synchronization Solution for iSCSI Targets Cluster Hosting Ceph RBD with Active/Active Connections

iSCSI is an IP based SAN technology, that carrying SCSI commands over TCP/IP. Ceph integrates iSCSI Target as a gateway to provide block layer storage service. A single iSCSI Target could be a system bottleneck because of its computing and I/O performance limitations. However, current software-defined iSCSI Targets can not cooperate on handling SCSI3 Persistent Reservation with each other in an iSCSI Target cluster. In this paper, we have proposed and implemented a mechanism that can synchronize the SCSI3 Persistent Reservation status of an iSCSI LUN among a cluster of Linux iSCSI Targets. By feats of this feature, it would become possible to set up a cluster of iSCSI Targets hosting mutual Ceph RBD images with active/active connections to meet high-performance and high availability requirements of modern business.