How are Vscan requests balanced between multiple Vscan servers?

Vscan Request Distribution:

• No specific algorithm (e.g., round-robin, least busy) is used to distribute Vscan requests.

• Each ONTAP AV Connector in a scanner-pool opens a named pipe to the SVM to listen for pending Vscan requests.

Named Pipe Operation:

• ONTAP places data into the named pipe, which operates on a first-in, first-out (FIFO) basis.

• The pipe functions like a message queue, preventing multiple servers from processing the same request.

• All AV Connectors place a READ call on the pipe, allowing them to see any new scan request written by the SVM.

Vscan Server Responsibilities:

• Each Vscan server (via its AV Connector) is responsible for reading and processing requests from the pipe in a timely manner.

• When the SVM writes a scan request to the pipe, all AV Connectors are notified and attempt to read it.

Request Processing:

• The first AV Connector to respond to a scan request removes it from the pipe, signaling to other AV Connectors that the request is being handled.

• This ensures only one AV Connector processes the request, preventing duplicate processing.

Acknowledgment and Communication:

• The responding AV Connector sends an ACK to the SVM, informing it which AV Connector is handling the scan request.

• ONTAP and the AV Connector do not decide which server processes a request; the first AV Connector to respond and acknowledge determines responsibility.