Questions asked during the Live Expert Webcast on September 16, 2014 with Cisco subject matter experts Varun Mehta and Anupam Asthana explaining the basics of Cisco UCS (Unified Computing System), show a demo around upgrade process, and share some troubleshooting tips and tricks with UCS. With lots of companies adopting Cisco UCS, there is need to understand the UCS architecture and the complete firmware upgrade procedure which would help customers/partners to maintain and operate the UCS environment effectively.
Q: What is the difference between Vifs and vNIC and vHBA which we create?
A: Vifs are called virtual interfaces -- VNic are ethernet virtual interfaces and VHBa are Fibre channel adapters used to carry storage traffic. A: vNICs are virtual NICs and vHBA are virtual HBA which together form VIFs. The number of Virtual Interface (VIF) is equal to sum of vNICs and vHBA which we create on the server/service profile.
Q: Will this firmware upgrade via firmware package take a longer time? I am assuming all the components will be upgraded together?
A: Host Firmware packages are used to upgrade the blades, Yes you are right they would be upgraded together.
Q: As i understand you have in gen 2 you have 32 gb throughput for hif ports if servers want to talk to each other does the traffic gets switched in the IOM or does it go to the FI's to get switched?
A: It depends on which path the server is sending the traffic. If the two server have traffic going through different Fabric Interconnect. The switching of traffic happens at the upstream but if the two servers are sending traffic through the same FI. The switching happens at the FI level.
Q: As there is a bottleneck between the IOM and FI's?
A: I am not clear what do you mean by bottleneck? If you are talking about over subscription. Then yes, we have depending on the type of IOM.
Q: When to configure 2204 & 2208 IOMs? Conditions for usage for IOMs?
A: I am not entirely clear with the question but IOM configuration/type of IOM usage depends on throughput we expect. We can have an IOM with just one uplink to FI or upto 8.
Q: My point is how to decide which IOM to use? Is it related to applications in use or blades?
A: That depends on the application/usage of the server. The selection of server is also done accordingly. Along with the VIC card and other server components (Raid Controller, RAM etc).
Q: What if Firmware is different while do RMA ? It will not get associated right?
A:You are absolutely correct. RMA/Replacement FI may not have the same firmware as the one you are running. In which case, we have to first bring up the RMA FI in standalone mode and upgrade/downgrade it to the version we have. After which we connect it back to the cluster.
Q: How do I ensure I have UCS server configured for redundancy?
A: We can do the following : a. When creating vNIC/vHBA ensure that we create them on both Fabric A & B b. Once the Service Profile creation is complete, check under vif paths to ensure we have vNICs and vHBAs on both fabrics and they are UP c. Check the output of #show mac address-table & #show npv flogi-table on both fabrics and ensure that the respective MAC Addresses and WWPNs are learnt on the Fabric Interconnects.
Q: What is HIF and NIF?
A: HIF is the short for Host InterFace . NIF is the short for Network InterFace. Cisco Blade Chassis connect to the network via IOM( IO Module ) , one each per fabric A & B. The server-facing ports on this IO Module are called HIF. These are internal ports. The network facing ports, which are used to connect the IOM to the Fabric Interconnect are called, NIF.
Q: What should I do if my upgrade gets stuck?
A: The Upgrade of any component takes around 15-25 minutes. Please be patient and allow it to complete. If it is still stuck check the status under the ‘General’ Tab and the Upgrade Status under the ‘FSM’ Tab. If there are any obvious error message try to address the reason for failure. Try to restart the operation. If it does not help, contact TAC for assistance.
Q: What should I do if server discovery is stuck?
A: Sometimes it takes multiple tries to complete. Please be patient and allow it to complete. If it is still stuck check the status under the ‘General’ Tab and the Upgrade Status under the ‘FSM’ Tab. If there are any obvious error message try to address the reason for failure ( for example a failed adapter etc. ). Try to restart the operation. If it does not help, contact TAC for assistance.