Evaluating the Effect of iSCSI Protocol Parameters on Performance.

Abstract

iSCSI is a new IETF standard protocol that makes it possi-ble for a SCSI initiator (client) on one machine to exchange SCSI commands and data with a SCSI target (server) on an-other machine connected via a TCP/IP network. When an initiator establishes a connection to a target, a large number of standard parameters can be negotiated in order to cus-tomize many aspects of that connection. Both the initiator and target implementations can configure other parameters outside the iSCSI standard that also customize their inter-actions with the SCSI environment. This paper reports the major results from an exten-sive study of the effect of these parameters on iSCSI per-formance. It also develops a linear relationship between a number of them. We suggest settings that offer the best per-formance in the situations tested, with the belief that these settings offer the best available general guidance for con-figuring iSCSI until results from testing in more complex situations becomes available.