Sun Storage 6580 Array
 
Sun Storage Flexline 280 Array
 
Sun Storage Common Array Manager (CAM)
 
Sun Storage 2510 Array
 
Sun Storage 2540 Array
 
Sun Storage 6180 Array
 
Sun Storage 2540-M2 Array
 
Sun Storage 6780 Array
 
Sun Storage 6140 Array
 
Sun Storage 2530-M2 Array
 
Sun Storage 2530 Array
 
Sun Storage Flexline 380 Array
 
Sun Storage 6540 Array
 
Sun Storage Flexline 240 Array
 
Sun Storage 6130 Array
 

PLA-Support>Sun Systems>DISK>Disk Software>SN-DK: CAM
 

Applies to:

Goal

This document describes the significance of a volume's "owning controller" and "preferred controller", and also explains how to change the "owning controller" setting of an individual volume via the Sun Storage Common Array Manager software.
This is often done in response to an xx.66.1010 alarm: "The following volume(s) is/are not managed by their preferred controller."
It also explains how changing the "owning controller" setting of a volume via CAM can result in a change of the "preferred controller" setting.

Solution

Every volume created on an Sun StorageTek [TM] 6000/2500/Flexline array has two different properties :

• owning controller (aka managing or current controller)
• preferred controller

To determine what the current settings of a volume are :

In the CAM GUI :

1. Click Sun Storage Common Array Manager.
   The navigation pane and the Storage System Summary page are displayed.
2. In the navigation pane, expand the array you want to work with, and choose Volumes.
   The "Volume Summary" page for that array is displayed.
3. Click the volume for which you want to review.
   The "Volume Details" page is displayed.

The preferred and owning controller settings for that volume are reported on this page.

Example :

In the CAM sscs CLI :

The owning and preferred controller settings for a volume are reported in the output of the following command :

Example :

Note that the owning controller is just listed as "Controller:" in this output

Significance of the "owning" and "preferred" controller settings :

The array has two controllers, A and B, and although both are active, at any time an individual volume will only be owned by one of the controllers. All I/O to that volume will be via the host path(s) to only that controller (unless ALUA is used). Different volumes may be owned by different controllers to balance overall I/O to the array.

The controller that currently owns the volume is referred to as its "owning controller" or sometimes as its "managing controller"

The volume's "preferred controller" is the "controller of choice" for that volume.
This is significant for a number of reasons, including :

• After the reboot of an array, the volumes will start out being owned by their preferred controller.
• An xx.66.1010 alarm will be generated by CAM if a volume is not owned by its preferred controller, and will persist until the volume is transferred back to being owned by its preferred controller
• Using the "Redistribute Volumes" function will attempt to move all volumes back to their preferred controller. For instructions on using this function see <Document 1568284.1> Sun Storage Common Array Manager: How to Redistribute Volumes on a Sun Storage 6000/2500/Flexline Array
• In (non-ALUA) host multipathing software the path(s) to the preferred controller will be classified as primary path(s) for a volume, and the path(s) to the other controller will be classified as secondary path(s)

Changing the "owning controller" setting of an individual volume :

In the CAM GUI :

1. Click Sun Storage Common Array Manager.
   The navigation pane and the Storage System Summary page are displayed.
2. In the navigation pane, expand the array you want to work with, and choose Volumes.
   The "Volume Summary" page for that array is displayed.
3. Click the volume for which you want to change controller ownership.
   The Volume Details page is displayed.
4. In the Owning Controller field, select the other controller (either A or B).
5. Click Save.

In the CAM sscs CLI :

The following command changes the owning controller to either A or B :

Example :

Consequences of changing the "owning controller" setting on the "preferred controller" setting :

In CAM only the owning controller is a user configurable setting - either the A or B controller can be selected. The preferred controller setting cannot be changed directly. The preferred controller may be changed indirectly, as a consequence of changing the owning controller setting.

 The following table shows all possible modifications that may be performed :

Note that on lines 1 and 2 (where the current preferred controller and owning controller already match) then changing the owning controller changes BOTH the owning and preferred controller settings of the volume.

If the preferred controller setting for a volume is changed via CAM then the "primary path" designation for the volume will be altered from an array perspective, which may not be reflected automatically in host multipath driver configurations. This can cause a disagreement between the array and associated hosts on the preferred controller for a volume, which in turn may cause xx.66.1010 alarms ("The following volume(s) is/are not managed by their preferred controller")

Changing the "preferred controller" setting of an individual volume :

In CAM it is not possible to change only the preferred controller setting of a volume. Generally, if the current owning controller and preferred controller are different there will be a host path issue which needs to be resolved - please refer to <Document 1136186.1> Troubleshooting Sun StorageTek 2500, Sun Storage 2500-M2, Sun Storage 6000: Volume Not on Preferred Path.

As described above, if the current owning controller and preferred controller are the same then changing the owning controller will also change the preferred controller to match.

Rarely, there will be a configuration issue where the owning controller and preferred controller are different and you want to change the preferred controller setting on the array to match the current owning controller. In this scenario it cannot be done directly in CAM, but it may be achievable by modifying the volume's owning controller twice, as follows :

References

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