When ACOS is deployed on a VMware ESXi virtualization platform, ESXi accesses ABS using the NFS protocol. The NFS I/O path is as shown below:
Each virtual machine corresponds to a directory, and each virtual volume corresponds to a group of NFS files within the associated directory. Depending on how the snapshot is implemented, the data file itself may also include some snapshot files. The NFS data link is maintained by the I/O Reroute service deployed on ESXi. It ensures long-term link stability through regular heartbeat checks with the Meta component of ABS. In most cases, the data link points to Access on the local SCVM of the ESXi.
The NFS client on ESXi converts the disk I/O of virtual machines into NFS requests and forwards them to Access on SCVM. All virtual volumes on an ESXi node share the same NFS data connection. Additional NFS connections might be used for HA functionality in vSphere, VAAI operations, or storage health checks; however, these connections do not handle actual data requests for virtual machines.
After the Access component receives an NFS I/O request, it converts it to an I/O request for the ABS volume. This completes the access from the VMware ESXi virtualization platform to ABS storage.
