User's Manual

Failback preference setting for HSV controllers
Table 11 (page 30) describes the failback preference mode for the controllers.
Table 11 Failback preference settings
BehaviorPoint in timeSetting
The units are alternately brought online to Controller 1 or to Controller 2.At initial presentationNo Preference
If cache data for a LUN exists on a particular controller, the unit will be
brought online there. Otherwise, the units are alternately brought online to
Controller 1 or to Controller 2.
On dual boot or controller
resynch
All LUNs are brought online to the surviving controller.On controller failover
All LUNs remain on the surviving controller. There is no failback except if a
host moves the LUN using SCSI commands.
On controller failback
The units are brought online to Controller 1.At initial presentationPath A - Failover
Only
If cache data for a LUN exists on a particular controller, the unit will be
brought online there. Otherwise, the units are brought online to Controller
1.
On dual boot or controller
resynch
All LUNs are brought online to the surviving controller.On controller failover
All LUNs remain on the surviving controller. There is no failback except if a
host moves the LUN using SCSI commands.
On controller failback
The units are brought online to Controller 2.At initial presentationPath B - Failover
Only
If cache data for a LUN exists on a particular controller, the unit will be
brought online there. Otherwise, the units are brought online to Controller
2.
On dual boot or controller
resynch
All LUNs are brought online to the surviving controller.On controller failover
All LUNs remain on the surviving controller. There is no failback except if a
host moves the LUN using SCSI commands.
On controller failback
The units are brought online to Controller 1.At initial presentationPath A -
Failover/Failback
If cache data for a LUN exists on a particular controller, the unit will be
brought online there. Otherwise, the units are brought online to Controller
1.
On dual boot or controller
resynch
All LUNs are brought online to the surviving controller.On controller failover
All LUNs remain on the surviving controller. After controller restoration, the
units that are online to Controller 2 and set to Path A are brought online to
On controller failback
Controller 1. This is a one-time occurrence. If the host then moves the LUN
using SCSI commands, the LUN will remain where moved.
The units are brought online to Controller 2.At initial presentationPath B -
Failover/Failback
If cache data for a LUN exists on a particular controller, the unit will be
brought online there. Otherwise, the units are brought online to Controller
2.
On dual boot or controller
resynch
All LUNs are brought online to the surviving controller.On controller failover
All LUNs remain on the surviving controller. After controller restoration, the
units that are online to Controller 1 and set to Path B are brought online to
On controller failback
Controller 2. This is a one-time occurrence. If the host then moves the LUN
using SCSI commands, the LUN will remain where moved.
Table 12 (page 31) describes the failback default behavior and supported settings when
ALUA-compliant multipath software is running with each operating system. Recommended settings
may vary depending on your configuration or environment.
30 EVA4400 operation