advertisement
Failback preference setting for HSV controllers
describes the failback preference behavior for the controllers.
Table 13 Failback preference behavior
Setting Point in time
No preference
Path A - Failover Only
Path B - Failover Only
At initial presentation
On dual boot or controller resynch
On controller failover
On controller failback
At initial presentation
On dual boot or controller resynch
On controller failover
On controller failback
At initial presentation
On dual boot or controller resynch
On controller failover
On controller failback
Path A - Failover/Failback
At initial presentation
Behavior
The units are alternately brought online to
Controller A or to Controller B.
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 A or to Controller B.
All LUNs are brought online to the surviving controller.
All LUNs remain on the surviving controller. There is no failback except if a host moves the LUN using SCSI commands.
The units are brought online to Controller
A.
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 A.
All LUNs are brought online to the surviving controller.
All LUNs remain on the surviving controller. There is no failback except if a host moves the LUN using SCSI commands.
The units are brought online to Controller
B.
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 B.
All LUNs are brought online to the surviving controller.
All LUNs remain on the surviving controller. There is no failback except if a host moves the LUN using SCSI commands.
The units are brought online to Controller
A.
HP StorageWorks 6400/8400 Enterprise Virtual Array User Guide 73
Setting Point in time
On dual boot or controller resynch
On controller failover
On controller failback
At initial presentation
On dual boot or controller resynch
Path B - Failover/Failback
On controller failover
On controller failback
Behavior
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 A.
All LUNs are brought online to the surviving controller.
All LUNs remain on the surviving controller. After controller restoration, the units that are online to Controller B and set to
Path A are brought online to Controller A.
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
B.
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 B.
All LUNs are brought online to the surviving controller.
All LUNs remain on the surviving controller. After controller restoration, the units that are online to Controller A and set to
Path B are brought online to Controller B.
This is a one time occurrence. If the host then moves the LUN using SCSI commands, the LUN will remain where moved.
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.
Table 14 Failback settings by operating system
Operating system
HP-UX
Default behavior
Host follows the unit
1
Supported settings
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
IBM AIX
Linux
Host follows the unit
1
Host follows the unit
1
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
74 EVA6400/8400 operation
Operating system
Novell NetWare
Default behavior Supported settings
Failback performed on the host
No Preference
Path A/B – Failover Only
OpenVMS
Sun Solaris
Tru64 UNIX
Host follows the unit
Host follows the unit
1
Host follows the unit
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback (recommended)
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback (recommended)
VMware
Host follows the unit
1
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
Windows Failback performed on the host
No Preference
Path A/B – Failover Only
Path A/B – Failover/Failback
1
If preference has been configured to ensure a more balanced controller configuration, the Path A/B – Failover/Failback setting is required to maintain the configuration after a single controller reboot.
Changing virtual disk failover/failback setting
Changing the failover/failback setting of a virtual disk may impact which controller presents the disk.
identifies the presentation behavior that results when the failover/failback setting for a virtual disk is changed.
NOTE:
If the new setting causes the presentation of the virtual disk to move to a new controller, any snapshots or snapclones associated with the virtual disk will also be moved.
Table 15 Impact on virtual disk presentation when changing failover/failback setting
New setting
No Preference
Path A Failover
Path B Failover
Path A Failover/Failback
Impact on virtual disk presentation
None. The disk maintains its original presentation.
If the disk is currently presented on controller B, it is moved to controller A. If the disk is on controller A, it remains there.
If the disk is currently presented on controller A, it is moved to controller B. If the disk is on controller B, it remains there.
If the disk is currently presented on controller B, it is moved to controller A. If the disk is on controller A, it remains there.
HP StorageWorks 6400/8400 Enterprise Virtual Array User Guide 75
advertisement
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Related manuals
advertisement