2002 - cesnet

16.2.2 Nishan–LinuxIn this test, the target was represented by the Nishan Systems IPS3300 commercialdevice. The initiator was running on a PC with the Linux operating system.The iSCSI router was connected to the disk array by the Fibre Channel interface.For the needs of the test, we divided the disk into four sections with sizesof 1 GB each. Client PCs were connected to the iSCSI router directly with theGigabit Ethernet without any intermediate devices that could affect the systemperformance.In client PCs having the initiator role, we used the iSCSI implementation of CiscoSystems. Other implementations contain a different iSCSI protocol version andtherefore turned out to be unusable.Performance Characteristics MeasurementsThe measurements were carried out using the iozone program with the followingparameters:iozone -Rb iscsi.wks -n 900m -g 900m -z -c -aModification of the TCP window size both for reading, and writing did not haveany substantial effect on the read/write performance compared to standardLinux kernel values (version 2.4.18 and 2.4.19). Modifications of the standardTCP socket buffer size for writing (16 kB replaced with 64 kB) and reading (85 kBreplaced with 1 MB) were performed.record size [kB] 4 8 16 32 64 128 256write 18060 17906 17780 18156 17909 18072 18020read 19916 17956 19602 19700 19865 19687 19774record size [kB] 512 1024 2048 4096 8192 16384write 18161 18084 17874 17693 17612 17708read 19390 19011 19579 19480 19228 19260Table 16.3: Read/Write values of Nishan IPS3300 [kBps]Practical ExperienceThe Nishan IPS3300 device seems to be a usable technology for the implementationof a storage area network (along with an appropriate disk array) utilizingthe iSCSI protocol.From the tested firmware versions, only the last one could be used for iSCSI.However, in this version, the part concerning SNS was unusable, hence thefunctionality of this protocol could not be tested.178 High-speed National Research Network and its New Applications 2002