The correct answer is D. Reduce the number of NFSv3 mounts to one.
NFSv3 is a network file system protocol that allows clients to access files stored on a remote server. NFSv3 uses TCP or UDP as the transport layer protocol, and typically runs on port 20491.
One of the known issues with NFSv3 mounts is that they can cause performance degradation and unresponsiveness on the client side if there are too many mounts or if there are network connectivity problems. This is because NFSv3 does not handle connection failures or timeouts gracefully, and may keep retrying to access the server indefinitely, blocking other processes or threads. This can result in slow disk speeds, high CPU usage, and system hangs23.
Therefore, one of the possible solutions to this issue is to reduce the number of NFSv3 mounts to one per hypervisor, instead of one per VM. This way, the hypervisor can manage the access to the shared storage appliance more efficiently, and avoid creating too many TCP connections or UDP packets that may overload the network or the server. Reducing the number of NFSv3 mounts can also simplify the configuration and troubleshooting of the network file system.
Increasing caching on the storage appliance may improve the read performance of the NFSv3 mounts, but it will not solve the underlying issue of connection failures or timeouts. Caching may also introduce data inconsistency or corruption issues if the cache is not synchronized with the server.
Configuring jumbo frames on the hypervisors and storage may improve the network throughput and efficiency of the NFSv3 mounts, but it will not solve the underlying issue of connection failures or timeouts.
Jumbo frames are larger than standard Ethernet frames, and require that all devices on the network path support them. Jumbo frames may also introduce fragmentation or compatibility issues if they are not configured properly.
Increasing CPU/RAM resources on affected VMs may improve their performance in general, but it will not solve the underlying issue of connection failures or timeouts. Increasing CPU/RAM resources may also be costly and wasteful if they are not needed for other purposes.