Storage Area Networks (SANs) provide a networking paradigm that provides easily reconfigurable connectivity between any subset of computers, disk storage, and switches. A SAN can contain a huge number of devices connected using switched fabric. A SAN that has thousands or tens of thousands of connected devices is difficult to administer using a simple disk group model. Veritas CommandCentral Storage software allows you to configure storage groups and storage accounts. Using the CommandCentral Storage software, you can allocate SAN storage more prudently and administer your complex SAN environments more effectively.
This feature of vxassist is designed to work in conjunction with SAL (SAN Access Layer) in Veritas CommandCentral Storage. When VxVM with SAN-aware vxassist is installed on a host where SAL is also installed, it is recommended that you create a user named root under SAL. This allows vxassist to use the root login to contact the SAL daemon (sald) on the primary SAL server without needing to specify the sal_username attribute to vxassist.
Figure: Dividing a Storage Area Network into storage groups, shows how you might choose to set up storage groups within a SAN.
In this example, the boundaries of the storage groups are based on the performance characteristics of different makes of disk array and on geographic location.
The vxassist utility in Veritas Volume Manager understands storage groups that you have defined using the CommandCentral Storage software. vxassist supports a simple language that you can use to specify how disks are to be allocated from pre-defined storage groups. This specification language defines the confinement and separation criteria that vxassist applies to the available storage to choose disks for creating, resizing or moving a volume.
To use the CommandCentral Storage storage groups with vxassist, perform the following steps in the order listed:
Use the CommandCentral Storage software to define one or more storage groups. Note that zoning is not an issue as it is completely independent of storage group creation.
Use the CommandCentral Storage software to attach attribute-value pairs to each storage group's property sheet. Typically, you would assign values for the following attributes: location, storage group, and protection.
Use the vxdiskadm command to configure the disks that you found in the previous step into VxVM disk groups.
Use vxassist to create volumes on disks that are selected by matching specified criteria for the values of storage group attributes. The usual restriction applies that a volume may only be created using disks from a single disk group.