12. Non-transitory tangible computer readable media that includes instructions for execution, which when executed by a processor, performs operations comprising: receiving, at an I/O adapter in a microserver chassis comprising a plurality of compute nodes and a shared storage resource, policy contexts prescribing storage access parameters of respective compute nodes; enforcing, at the I/O adapter, the respective policy contexts on I/O operations by the compute nodes, wherein a particular I/O operation by any compute node is not executed when the respective policy context does not permit the particular I/O operation; allocating tokens to command descriptors associated with I/O operations for accessing the shared storage resource; identifying, at the I/O adapter, a violation of any policy context of any compute node based on availability of the tokens; and throttling I/O operations by other compute nodes until the violation disappears.
15. The media of claim 12 , wherein enforcing the respective policy contexts comprises: receiving at a sNIC of the I/O adapter, a SCSI packet generated by one of the compute nodes, the sNIC being uniquely associated with the compute node, the I/O operations by the compute node comprising a SCSI command; encapsulating, at the sNIC, the SCSI packet in an Ethernet packet comprising a fake preset destination address and source address in an Ethernet header; filtering, at a packet classifier of the I/O adapter, the Ethernet header based on the fake preset destination address and source address, wherein the packet classifier returns a key based on the filtering; indexing into a flow table in the I/O adapter with the key, the flow table comprising a plurality of flow table entries specifying respective actions, at least one of the actions including calling an arbiter routine that varies according a type of the SCSI packet; and executing the arbiter routine.