MULTI PATH FAILOVER

Description:
 	Project provides the ability to configure redundant SCSI busses
	to avoid single points of failure, improving availability.
	Failover between different SCSI busses on supporting controllers
	is supported on HSZ, HSG.

	Failover between SCSI direct paths and served paths is also
	implemented.

P0 deliverables: software to support this switching and to support
	naming changes implemented in conjunction with the new HSZ
	firmware.

LOP:	PS, IR, FS, DS, PP all done. DS and FS have been updated to
	reflect actual code.

Schedule: QTV testing has begun of some functions. Unit testing to
	check naming, autoconfig, SCSI-SCSI failover, and SCSI-MSCP
	failover shows all working, save for a known DUdriver 
	limitation which can readily be fixed (per H. Read). Support
	for this is already in the switching code. 

	Final testing of SCSI-SCSI naming requires real HSZ firmware,
	not yet available.

	Code integration: original target 8/30. Actual: in process.

Defect Containment:
	LOC prediction: 5500 LOC.
	    actual:     5800 LOC
	Defect prediction: 220
	       actual:	   390

Dependences:
	Reliable SCSI-MSCP failover depends on DUdriver mod to
	complete I/Os if connection fails rather than hang onto
	them.

	Final checkout of SCSI naming mods (in IOGEN and MANAGE) needs
	at least one HSZ with the firmware that passes device allocation
	class.

	QIOserver will use this software to fail between QIOserver,
	MSCP, and direct paths. The QIOserver mods however need to be
	written.

Issues:
	Major one is that tomorrow is my last day. I will be reachable
	at Everhart@GCE.Com to help with code reviews, but it has not
	been possible to schedule code review sooner.