Check Storage Area Network Configuration Setting

The role of the virtual storage private network is read write data and synchronize data in virtual storage. If the virtual storage is abnormal, it will critically impact customer business and even cause data loss. When the virtual storage private network prompts packet loss alarm, or the virtual storage reads or writes abnormal, you can troubleshoot the virtual storage private network by following the steps below.

Generally, you may first check whether the virtual storage private network configuration on the Sangfor HCI is normal and configured correctly. Sangfor HCI virtual storage private network has 3 deployment modes to choose from:

1. Standard link aggregation (recommended)

   In this scenario, if 2 switches are used kindly ensure they are configured in stack mode and the appropriate load balancing mode is also configured. Otherwise, it will potentially cause the virtual storage become abnormal.

2. Link aggregation disabled

   In fact, there is only one switch, and each host has a storage interface. When an interface failed or switch failure in this deployment mode will cause virtual storage to become abnormal.

3. Link aggregation with one switch

   Two storage network interfaces of each host are connected to one switch. Please be noted that the switch does not need to be configured with link aggregation, but it’s recommended to configure a VLAN to isolate the storage interfaces. Apart from that, with link redundancy, the failure of a storage interface on a single host does not affect the normal use of virtual storage. However, if the switch fails, the entire virtual storage will be disconnected. We recommend stack two switches to achieve link and switch redundancy.

4. Link aggregation with two switches

   The highest fault tolerance deployment mode is link aggregation with two switches. Both links and switches have redundancy. The two switches are independent from each other. If the switches are stacked, then link aggregation with one switch deployment mode should be selected and ensure there’s no link connected between the switches to prevent the storage data looping, in which will cause data forward abnormal. In a 2 hosts cluster, the storage interfaces deployment method is highly recommended to directly connected between hosts and the link aggregation with two switches for the storage network deployment should be selected.

Verify how the virtual storage network is connected and whether the switch is configured with stacking. If stacking is configured, select link aggregation with one switch. Incorrect virtual storage network configuration can cause virtual storage to behave anomaly and change of the storage area network will require to shut down all virtual machines before the operation.

Check the Storage Switch Cable Connection and the Configuration

If the virtual storage configuration is correct but it still experiencing issue with the link failure or packet loss, then might require moving forward to check on the switch cable connection and network port configuration.

1. Standard link aggregation

   If 2 switches are used, they must be configured in stack mode and the appropriate load balance mode must be configured in both the Sangfor HCI and connected switch(es).

2. Link aggregation disabled

   It is recommended assign storage area network port to a VLAN on the switch to prevent broadcast/multicast packets from other networks, which affecting the stability of the storage network communication. Check whether the storage port of the host has the wrong cable connection on the switch. It does not need any additional configuration on the switch instead of VLAN configuration.

3. Link aggregation with one switch

   It is emphasized that switch does not need any link aggregation configuration for storage network aggregation deployment. In the case of a stack switches, it is recommended connect two storage ports of the hosts to two switches respectively, prevent a single point of failure of the switch and causing a virtual storage network interruption.

4. Link aggregation with two switches

   Try not to interconnect two switches with network cables or through a third switch. If you must interconnect, divide the VLAN of the interconnect port from the VLAN of the storage port.

5. Finally, not forget to check whether the storage port is connected to the wrong switch port, this will potentially cause the virtual storage network abnormal or failure.

Check the Compatibility of the SFP Module and the Fiber Cables

It is recommended to use 10G network port deployment for the virtual storage private network, otherwise there will be a bandwidth performance bottleneck. Generally, the 10 Gigabit network ports of the server are all optical ports, and fiber optic cable used to connect to the switches.

Fiber optic modules are divided into multi-mode and single mode. If the fiber optic modules connect to wrong types of fiber cable, it will cause large optical attenuation, and packet loss or data interruption may occur.

How to differentiate fiber optic module:

Unplug the optical module and check the model of the optical module. If the model has SM, it is a single mode fiber. Module model with MM is multimode fiber.

The following figure shows the multi-mode optical module:

Optical fibers can be distinguished by the colour of the fiber jumper:

Single mode fiber: Fiber jumpers are shown in yellow colour, while connectors and protective sleeves are blue; transmission distance is longer.

Multi-mode fiber: Fiber jumpers are shown in orange colour, and some are shown in gray. The connectors and protective sleeves are beige or black; transmission distance is short.

If the optical fiber and optical modules do not match, you need to coordinate the replacement of optical fibers or optical modules. Ensure the matching use of fiber optic modules.

Generally, if an alarm network port occasionally loses packets and the network port uses a fiber optic module, it is recommended to check on the fiber optic module first.

Collect The Information and Escalate to Specialist

If the issue did not resolve after the above troubleshooting steps, kindly collect the following information, and seek expertise assistance:

1. Sangfor HCI version.
2. Screenshots of storage area network anomalies.
3. Topology on the storage area network and switch.
4. Virtual storage speed test result.