Chen, More than likely, the bottleneck in your data transfer is the speed at which bits are read from the physical disk in your Xserve. You can measure data rates off the disk in a variety of ways. The one I prefer is "iostat." 12 to 13 MB/sec sounds almost exactly like a single IDE drive. You can improve the speed of a data storage device by striping data across several drives (in a RAID set), or in a variety of other ways. Good luck with this. Data motion is a bottleneck for many of us. -Chris Dwan The BioTeam On Jul 9, 2004, at 5:41 AM, Chen Peng wrote: > Hi, > > We are runing a Xserve G4 cluster with SMC gigabit switch. I found the > network performance is not satisfactory that file transmission speed > is always limited to 12MB/s to 13 MB/s. > > To copy a 800MB file from one host (192.168.101.161) to another one > (192.168.101.162) using FTP, it takes almost 70 seconds when the > entire network is almost idle. I have verified all NIC and ports on > the switch, all of them appear to be "1000base TX". And the disk IO > speed is guaranteed to be over 40MB/s. > > We expect the average speed in gigabit ethernet should be around > 30MB/s. Does any one know what might be the problem? > > Thank you. > > -- > Chen Peng > <chenpeng@alumni.nus.edu.sg> >