Dynamic path selection policy for multipathing in a virtualized environment

One or more computer-readable non-transitory storage media embodying software to change a current storage I/O path used by a host computer to access networked storage to an alternative storage I/O path by considering traffic load at a networked switch in the current storage I/O path, the host computer comprising a processor and first and second host bus adapter ports, wherein the current storage I/O path from the host computer to the networked storage is established through the first host bus adapter port and the networked switch and the processor is configured to execute the software to:

• transmit a request to the networked switch in the current storage I/O path to provide network load information currently experienced by the networked switch;
• receive network load information from the networked switch;
• evaluate whether the networked switch is overloaded based on the received network load information;
• select a new alternative storage I/O path to the networked storage that does not include the networked switch based on the evaluation, the new alternative storage I/O path being established through the second host bus adapter port and a different networked switch that is networked with the second host bus adapter port;
• forward future storage I/O communications to the networked storage through the second host bus adapter port and using the new alternative storage I/O path;
• and
• wherein the processor is configured to execute the software to evaluate whether the networked switch is overloaded by comparing the received network load information against a threshold value, and the threshold value is a maximum ratio of load at the networked switch in the current storage I/O path to an average load at any other networked switches including the different networked switch along any alternate storage I/O paths between the host computer and the networked storage.

A host computer comprising:

• one or more processors;
• first and second host bus adapter ports;
• and
• a memory coupled to the processors comprising instructions executable by the processors to change a current storage I/O path used by the host computer to access networked storage to an alternative storage I/O path by considering traffic load at a networked switch in the current storage I/O path, wherein the current storage I/O path from the host computer to the networked storage is established through the first host bus adapter port and the networked switch and the processors execute the instructions to:
• transmit a request to the networked switch in the current storage I/O path to provide network load information currently experienced by the networked switch;
• receive network load information from the networked switch;
• evaluate whether the networked switch is overloaded based on the received network load information;
• select a new alternative storage I/O path to the networked storage that does not include the networked switch based on the evaluation, the new alternative storage I/O path being established through the second host bus adapter port and a different networked switch that is networked with the second host bus adapter port;
• forward future storage I/O communications to the networked storage through the second host bus adapter port and using the new alternative storage I/O path;
• and
• wherein the executed instructions to evaluate whether the networked switch is overloaded further comprise instructions to compare the received network load information against a threshold value and the threshold value is a maximum ratio of load at the networked switch in the current storage I/O path to an average load at any other networked switches including the different networked switch along any alternate storage I/O paths between the host computer and the networked storage.