On Thu, 2011-07-28 at 13:42 +0200, Fubo Chen wrote: > On Sat, Jul 23, 2011 at 10:45 AM, Nicholas A. Bellinger > <nab@xxxxxxxxxxxxxxx> wrote: > > This patch adds support for RFC-3720 compatiable ErrorRecoveryLevel > > support as defined in Section 6.1.5. Error Recovery Hierarchy. > > > > This includes support for iSCSI session reinstatement, iSCSI within > > command and within connection recovery, and explict/implict connection > > recovery (CSM-E and CSM-I) from state machines in Section 7 of RFC-3720. > > > > These functions are called from iscsi_target.c to handle processing > > based on the negotiated session-wide ErrorRecoveryLevel parameter. > > > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> > > This is interesting. Is ERL2 similar to md ? If so, when should I use > md and when ERL2 ? > I think you mean dm-multipath and not md RAID here.. dm-multipath with TCM's ALUA multipath code provides a fabric independent (iSCSI, FCoE, FC, SRP, etc) method of path failover across multiple target ports for LUNs with a matching IEEE Extended Registered WWN. ERL=2 is a fabric dependent method of performing iSCSI connection recovery on one or more failed TCP connections, where outstanding I/O can be implictly retried and/or explictly migrated (TASK_REASSIGN) to an active connection without having to restart the iSCSI I_T Nexus, or notify the client side multipath layer that a I_T nexus has been lost. Their use is not mutually exclusive, and can be used together to complement one another. --nab -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
