PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.1 (Linux)

A.1.6 Creating Group Hierarchy

The following eight kinds of group hierarchical structures, including a nonhierarchical structure, are available.

higher level group <----------------------------------------------> lower level group
mirror group (*1)
mirror group (*1) - stripe group (*3)
mirror group (*1) - stripe group (*3) - concatenation group (*8) 
mirror group (*1) - concatenation group (*6)
stripe group (*2)
stripe group (*2) - concatenation group (*7)
concatenation group (*4)
switch group (*5)

Possible operations on groups at each hierarchical level that change the structure are as follows.

 

(*1) The highest level mirror group

• Disks, lower level stripe groups, and lower level concatenation groups can be connected or disconnected. However, disconnection is impossible if it can change the volume configuration or status.
• If no volume exits, the group itself can be removed.
• Volumes can be created or removed.

   

(*2) The highest level stripe group

• If no volume exists, disks and lower level concatenation groups can be connected or disconnected.
• If no volume exists, this type group can be connected to a mirror group.
• If no volume exists, the group itself can be removed.
• If more than one disks or lower level concatenation groups are connected to, volumes can be created or removed.

   

(*3) The lower level stripe group

• This type group can be disconnected from the highest level mirror group. However, disconnection is impossible if it can change the volume configuration or status.

   

(*4) The highest level concatenation group

• Disks can be connected.
• If no volume area exists on the disk that was connected last, that disk can be disconnected.
• If no volume exists, this type group can be connected to a mirror group or a stripe group.
• If no volume exists, the group itself can be removed.
• Volumes can be created or removed.

   

(*5) The highest level switch group

• Disks can be connected.
• If no volume or inactive disk exists, the active disk can be disconnected.
• The inactive disk can be disconnected.
• If no volume exists, the group itself can be removed.
• Volumes can be created or removed.

   

(*6) Lower level concatenation group connected to the highest level mirror group

• Disks can be connected.
• If more than one disk is connected and no volume area exists on the disk that was connected last, that disk can be disconnected.
• This type group can be disconnected from the highest level mirror group. However, disconnection is impossible if it can change the volume configuration or status.

   

(*7) Lower level concatenation group connected to the highest level stripe group

• If no volume exists within the highest level stripe group, disks can be connected.
• If more than one disk is connected and no volume exists within the highest level group, the disk that was connected last can be disconnected.
• If no volume exists within the highest level stripe group, this type group can be disconnected from the highest level stripe group.

   

(*8) Lower level concatenation group connected to a lower level stripe group

• None.