IBM DS6000 Series manual Volume Group

Volume groups can be thought of as LUN groups. Do not confuse the term volume group here with that of volume groups on pSeries. The DS6000 Storage Manager volume groups have the following properties:

￿Volume groups enable FB LUN masking.

￿They contain one or more host attachments from different hosts and one or more LUNs. This allows sharing of the volumes/LUNs in the group with other host port attachments or other hosts that might be, for example, configured in clustering.

￿A specific host attachment can be in only one volume group. Several host attachments can be associated with one volume group. For example, a port with a WWPN number of 10000000C92EF123, can only reside in one volume group, not two or more.

￿Assigning host attachments from multiple hosts systems, even running different operating system types, is allowed in the same volume group.

Note: We recommend configuring one host per volume group.

Volume Group 1 Host

Host Attachment

pSeries1

Volume Group 2

xSeries2

Figure 9-3 Diagram of the relationship of a host attachment to a volume group

In Figure 9-3,we show two volume groups, Volume Group 1 and Volume Group 2. A pSeries server with 1 host attachment (four ports grouped in that attachment) resides in Volume Group1. The xSeries2 server has 1 host attachment (2 ports grouped into the attachment). The ports are grouped together in one attachment definition, for example, the server, xSeries2, is dual pathed to the LUNs through one attachment group definition.

￿In order to share LUNs across multiple host attachments, LUNs can be in more than one volume group as shown in the example in Figure 9-4 on page 158.

Chapter 9. The DS Storage Manager: Logical configuration 157