tailieunhanh - Managing NFS and NIS 2nd phần 10

Một mạng được thiết kế để đảm bảo truy cập trong suốt đối với hệ thống tập tin và để cung cấp dịch vụ "plugand-play" cho các khách hàng mới là một ứng cử viên cho việc mở rộng thường xuyên. Tham gia các mạng độc lập với thiết bị định tuyến, chuyển mạch, trung tâm, cầu, hoặc lặp có thể thêm vào mức độ giao thông | Managing NFS and NIS Chapter 17. Network Performance Analysis This chapter explores network diagnostics and partitioning schemes aimed at reducing congestion and improving the local host s interface to the network. Network congestion and network interfaces A network that was designed to ensure transparent access to filesystems and to provide plug-and-play services for new clients is a prime candidate for regular expansion. Joining several independent networks with routers switches hubs bridges or repeaters may add to the traffic level on one or more of the networks. However a network cannot grow indefinitely without eventually experiencing congestion problems. Therefore don t grow a network without planning its physical topology cable routing and limitations as well as its logical design. After several spurts of growth performance on the network may suffer due to excessive loading. The problems discussed in this section affect NIS as well as NFS service. Adding network partitioning hardware affects the transmission of broadcast packets and poorly placed bridges switches or routers can create new bottlenecks in frequently used network virtual circuits. Throughout this chapter the emphasis will be on planning and capacity evaluation rather than on low-level electrical details. Local network interface Ethernet cabling problems such as incorrect or poorly made Category-5 cabling affect all of the machines on the network. Conversely a local interface problem is visible only to the machine suffering from it. An Ethernet interface device driver that cannot handle the packet traffic is an example of such a local interface problem. The netstat tool gives a good indication of the reliability of the local physical network interface netstat -in Name Mtu Net Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue lo0 8232 7188 0 7188 0 0 0 hme0 1500 139478 11 102155 0 3055 0 The first three columns show the network interface the