2002 - cesnet

• data space consolidation (easy transition from a local, directly connecteddisc space to a disc space connected via an IP network)• storage area networks (local, distributed)• data replication• backup on the level of physical devices• network boot and its use for high availability data systems• data space provision services and remote data access16.2 Testing of iSCSI DevicesWithin the configurations described below, we tested the individual iSCSI implementationsin the Linux operating system, and Nishan and Cisco devices.Our measurements focused on the basic functionality and performance characteristics.In addition, we tested several other functions (authentication, iSCSInetboot) and summarized the results in the CESNET technical reports No. 5/2002, 12/2002, and 15/2002. From the previously mentioned reports, selectedperformance characteristics and some other facts revealed during testing areprovided below.Considering that every measurement took place at a different time, differentclient devices and network elements were available. Therefore, measurementscannot be compared directly with one another. However, it is possible to comparemeasured characteristics with the situation when a hard drive is connecteddirectly to a client as a local device.IPinitiatortargetFigure 16.1: Testing configurationdiskdeviceAs in the case of the classic SCSI, the command sender is called the initiatorand the command executor is called the target. The network entity referred toas the client includes one or more initiators and network interfaces, the serverentity includes one or more targets and network interfaces. Every node has itsunique world identification. Both parties communicate with each other via theTCP protocol, the server listens at port 5003 according to [SSC02].For measuring the iSCSI performance, we employed the utest tool, which was apart of the Intel implementation source, and a standard iozone 13 benchmark.13http://www.iozone.org/High-speed National Research Network and its New Applications 2002175