An is a special that the uses to communicate management request information and event information between the and the in a storage array network environment.
The definition for the access virtual disk is built into the configuration information. From the point of view of the host and the RAID controller modules, the access virtual disk has a address. The default LUN is 31. The access virtual disk, however, does not have any physical disks assigned to the LUN.
You can manage a storage array in two ways:
For out-of-band management, the host sends data to the RAID controller module in the storage array over the host-to-RAID controller module interface cables. The storage management station sends commands to the RAID controller module through a separate Ethernet cable. Also, the RAID controller module sends events to the storage management station through the Ethernet cable. Commands and events are separate from the data.
For in-band management, the host sends data to the RAID controller module in the storage array through the host-to-RAID controller module interface cables. The storage management station also sends commands to the RAID controller module through the host-to-RAID controller module interface cables. The RAID controller module sends events to the storage management station through the host-to-RAID controller module interface cables. Commands and events are mixed with the data.
For the in-band management method to operate, the storage array must have an access virtual disk. The access virtual disk provides the host operating system (OS) a procedure for finding the storage array. Without the access virtual disk, the host OS cannot find a storage array that is connected to the host.
The access virtual disk uses approximately 20 MB of storage space. The access virtual disk storage space is not available for data storage.
In summary, the access virtual disk has the following characteristics:
Attention:
Loss of management access – Removing an access virtual disk causes loss of in-band management access from the host or host group with which the access virtual disk is associated.
Note:
The access virtual disk is not visible to the Linux operating system using the MPP failover driver.