PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.1 (Solaris(TM) Operating System)
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Chapter 2 Objects> 2.7 GDS Snapshot Objects> 2.7.2 Shadow Object

2.7.2.2 Shadow Disk

A physical disk registered with a shadow class is called a shadow disk. A shadow disk is the shadow object corresponding to an SDX disk that is an SDX object.

When SDX disks and shadow disks do not have to be classified particularly, they may be called "disks" collectively.

 

Attributes

A shadow disk has the following attributes.

Name
This attribute identifies the shadow disk within a shadow class. There are the following restrictions.
Type
This attribute indicates the type of shadow disk. Either of the following values will be set.
Mirror
The disk has been connected to a mirror group.
Stripe
The disk has been connected to a stripe group.
Concatenation
The disk has been connected to a concatenation group.
Single
A shadow volume can be created without connecting to a shadow group.
Undefined
The disk has been registered with the shadow class without its usage being specified.

 

Operation

The operation other than status display is not available from Management View. Use the command for each operation.

Create
A disk will be created by registering a physical disk with a certain shadow class using the sdxshadowdisk -M command.
Delete
The shadow disk can be deleted from a shadow class with the sdxshadowdisk -R command.
Connect
The shadow disk can be added to a certain shadow group with the sdxshadowdisk -C command.
Disconnect
The shadow disk will be disconnected from the shadow group with the sdxshadowdisk -D command.
Status Display
The shadow disk status can be displayed with the sdxinfo command. For details on GDS Management View, see "Viewing Configurations and Monitoring Statuses."

 

Status

A shadow disk can have the following status.

ENABLE
The shadow disk is in the normal status.

 

Reference

There are the following points of concern for shadow disks.

Rules
Number of Disks
Important Points
Restraining Access to Physical Special File
Initializing Disk
Disk Size

 

The physical disk that is registered with a class in a certain domain (domain alpha) with the sdxdisk -M command and accordingly is managed as an SDX disk can be registered with a shadow class in another domain (domain beta) with the sdxshadowdisk -M command and accordingly be managed as a shadow disk. The shadow disk must be named as same as the SDX disk.


[Figure: An SDX Disk and a Shadow Disk]


The physical disk (c1t1d2 in the figure below) to which the private slice has been copied with the disk unit's copy function from the physical disk that is registered with a class in a certain domain (domain alpha) with the sdxdisk -M command and accordingly is managed as an SDX disk (c1t1d1 in the figure below) can be registered with a shadow class in the same domain (domain alpha) or in another domain (domain beta) with the sdxshadowdisk -M command and accordingly be managed as a shadow disk. The shadow disk must be named as same as the SDX disk.


[Figure: Disk Unit's Copy Function and a Shadow Disk]


Physical Device Name
The same physical device name (such as c1t1d1) is not necessarily assigned to the identical physical device in domain alpha and domain beta.



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