Veritas InfoScale™ Virtualization Guide - Linux on ESXi

Achieving storage visibility using Dynamic Multi-Pathing in the hypervisor

When DMP is installed in the hypervisor, DMP provides instant visibility to the storage attributes of a LUN. You can use the storage attributes to determine the characteristics of the LUN.

The following scenario describes a typical use case for storage visibility.

As the ESX administrator, you notice that your existing pool of storage is getting near capacity, so you put in a requisition to your storage team to add additional storage. You request two LUNs to meet the storage needs of different tiers of applications:

After the storage team processes the request, you get an email from the storage admin stating "Your storage is ready". Without any more information, you need to guess which LUN is which, and has the appropriate storage configuration (RAID 5 vs. RAID 0+1).

You need to determine which LUN is which, so that you can set up the applications on the appropriate storage. If you allocate mission critical, high performance applications to a RAID 5 LUN, SLA's could be impacted, and the applications may run slower than needed. Conversely, you want to avoid allocating low-priority applications on the high-end storage tier.

DMP provides instant visibility to the storage attributes of a LUN so you can determine exactly which device is which.

Navigate to the storage view, and you can see the LUNs. The attributes for each LUN show which LUN is RAID 5 and which is RAID 0+1.

Figure: Storage view showing the LUN RAID configuration

The storage attributes also let you identify the LUN using the AVID name. The AVID name provides a clear way to refer to the device, and can reduce confusion between the ESXi system administrator and the storage administrator.

Figure: Storage attributes showing AVID name

If an issue occurs for the LUN, you can refer to the storage device by the AVID name. For example, if one of the LUNs has a performance issue, you can communicate that to the platform or storage administration team. The AVID name provides a common, concise language between the platform and storage administration teams, and minimizes any confusion. It also speeds time to remediation of issues, and reduces ambiguity in communications.