How to Reduce the Risk of SAN Service Outages with Topology Views

From time to time you will need to upgrade firmware on your switches or your arrays. Additionally, there are sometimes unexpected hardware failures within the SAN environment. In both of these scenarios it is critical that you understand which hosts and applications are potentially affected by the changes.

Whether you are managing a change or an unplanned outage it is critical that you can inform the user community quickly and proactively about issues that may impact their hosts or applications.

 In this blog I will demonstrate examples of identifying the following:

• Physical hosts that are connected to a storage array
• Physical hosts that only have a single path to the storage array
• Virtual hosts that are connected to a storage array
• Virtual hosts that only have a single path to the storage array

Physical Hosts Connected To A Storage Array

If you have a situation in which you are upgrading the firmware on a storage array or you have an unexpected outage it is important to understand which physical hosts are connected to the storage array in question:

Figure 1: Host Connections to Storage

Figure 1 shows the connectivity for all physical hosts connected to the DSS named “SDB000000001”. You can export this to a PDF for attachment to a case or email. You also might choose to list the hosts (masking views) associated with any give DSS in the form of a table that you could export to a CSV.

Figure 2: List of Hosts

Physical Hosts That Only Have A Single Path To The Storage Array

Prior to executing a firmware change you should ensure that you do not have any hosts/masking views with single paths to the fabric that might be affected by a change. IntelliMagic provides reports that identify any hosts with a single path through the fabric as shown Figure 3:  Hosts with a Single Path to Storage below:

Figure 3: Hosts with a Single Path to Storage

Virtual Hosts That Are Connected To A Storage Array

In addition to identifying physical hosts connected to a storage array it is important to understand the virtual hosts connected to a storage array. Because this could be a long list I am only showing an example of a subset of the VMs associated with a selected DSS (SDBSA04VNXS19):

Figure 4: VMware Hosts Associated with Storage Array

Virtual Hosts That Only Have A Single Path To The Storage Array

Prior to executing a firmware update on your switches or your storage arrays you should double check to make sure you understand if there are any ESX hosts that are affected by single paths. The following chart shows you if there are any ESX hosts with a single path:

Figure 5: ESX Hosts with Single Switch Link

To see which VM’s are affected you just need to drill down and see the list of VMs associated with the ESX host.

Reduce Risk of Service Outages with Topology Views

When you need to perform a firmware upgrade or have an unexpected outage it is very important to be able to quickly see which physical and virtual hosts are connected to which storage arrays.

IntelliMagic Vision for SAN’s powerful dynamic topology maps with filtering can help you quickly identify which hosts are connected to switches and storage that are impacted. This provides you with the information you need to reduce risk of outage by identifying sub-optimal configurations and providing all the connectivity information you need to make intelligent and actionable decisions.