  We report on our investigations on some technologies that can be used to
build disk servers and networks of disk servers using commodity hardware and
software solutions. It focuses on the performance that can be achieved by these
systems and gives measured figures for different configurations.
  It is divided into two parts : iSCSI and other technologies and hardware and
software RAID solutions.
  The first part studies different technologies that can be used by clients to
access disk servers using a gigabit ethernet network. It covers block access
technologies (iSCSI, hyperSCSI, ENBD). Experimental figures are given for
different numbers of clients and servers.
  The second part compares a system based on 3ware hardware RAID controllers, a
system using linux software RAID and IDE cards and a system mixing both
hardware RAID and software RAID. Performance measurements for reading and
writing are given for different RAID levels.
