HACMP and NIS.doc

关于HACMP在NIS环境下使用的注意事项PowerHA SystemMirror HACMP Version 6.1 Administration guide 7x24 maintenance Planning for 7x24 maintenanceNetwork configuration and name servingSetting up and maintaining clear communication paths for the Cluster Manager is a key element for efficient cluster operation.Setting up serial networks or other heartbeat pathIt is crucial to have at least one serial network configured for the cluster. Without a serial network, you run the risk of a partitioned cluster if TCP/IP networks fail, since the nodes will be unable to maintain heartbeat communication. You can also use disk heartbeats or heartbeats over IP aliases to maintain cluster communications.Integrating HACMP with network services（结合网络服务的HACMP）HACMP requires IP address to name resolution during the configuration process. The three most commonly used methods include: Domain Name Service（DNS） Network Information Service（NIS） Flat file name resolution (/etc/hosts).（Local）By default, a name request will look first for the DNS (/etc/resolv.conf), second for NIS, and last for /etc/hosts to resolve the name. Since DNS and NIS both require certain hosts as designated servers, it is necessary to maintain the /etc/hosts file in case the DNS or NIS name server is unavailable, and to identify hosts that are not known to the name server. It is required to have all HACMP IP labels in all cluster nodes /etc/hosts tables.To ensure the most rapid name resolution of cluster nodes, change the default order for name serving so that /etc/hosts is used first (at least for cluster nodes).To do this, edit the /etc/netsvc.conf file so that this line appears as follows:hosts=local,bindPutting the local option first tells the system to use /etc/hosts first. If your installation uses NIS you can also add nis. For example, hosts=local,bind,nisYou can also change the order for name resolution by changing the environment variable NSORDER as follows:NSORDER=local,bind,nis默认的解析顺序为：DNS NIS LocalDNS(/etc/resolv.conf)NISLocal(/etc/hosts)改变解析顺序有两种办法：（1） 在/etc/resolv.conf中加一行：hosts=local,bind,nis（2） 修改环境变量NSORDER的值：NSORDER=local,bind,nisNote: By default, during the process of IP address swapping, to ensure that the external name service does not cause AIX to map the service IP address to the wrong network interface, HACMP automatically disables NIS or DNS by temporarily setting the AIX environment variable NSORDER=local within the event scripts. If you are using NIS, have the NIS master server outside the cluster, and have the cluster nodes run as NIS slave servers. At a minimum, every HACMP node must be able to access NIS master or slave servers on a local subnet, and not via a router.NIS主/从服务器需要与HACMP节点同属一个本地子网，不经过路由器。See the Planning Guide and the Installation Guide for information on editing the /etc/hosts file, and also for notes on NIS and cron considerations.Important: You cannot use DHCP to allocate IP addresses to HACMP cluster nodes. Clients may use this method, but cluster nodes cannot.Once configuration is complete, name resolution is no longer required and is not used by HACMP cluster services.Tuning networks for best performance调整至最佳网络性能HACMP provides easy control over several tuning parameters that affect the clusters performance. Setting these tuning parameters correctly to ensure throughput and adjusting the HACMP failure detection rate can help avoid failures caused by heavy network traffic.Cluster nodes sometimes experience extreme performance problems, caused by large I/O transfers, excessive error logging, or lack of memory. When this happens, the HACMP daemons can be starved for CPU time. Processes running at a priority higher than the RSCT or Cluster Manager subsystems can also cause this problem.The deadman switch is an AIX kernel extension that halts a node when the Cluster Manager does not run for a certain amount of time, usually due to one of the problems noted above.See Configuring AIX for HACMP in the Installation Guide for information on setting tuning parameters correctly to avoid some of the performance problems noted above./etc/hostsThe cluster event scripts use the /etc/hosts file for name resolution. All cluster node IP interfaces must be added to this file on each node.HACMP may modify this file to ensure that all nodes have the necessary information in their /etc/hosts file, for proper HACMP operations.If you delete service IP labels from the cluster configuration using SMIT, we recommend that you also remove them from /etc/hosts. This reduces the possibility of having conflicting entries if the labels are reused with different addresses in a future configuration.Note that DNS and NIS are disabled during HACMP-related name resolution. This is why HACMP IP addresses must be maintained locally.当HACMP进行相关名字解析的时候DNS和NIS将会被禁用。Important: If you manage user accounts with a utility such as Network Information Service (NIS) or Distributed Computing Environment (DCE) Manager, do not use HACMP user management. Using HACMP user management in this environment might cause serious system inconsistencies in the database.如果使用NIS或者DCE管理用户，不要使用HACMP用户管理。For example, an HACMP cluster node may be a client in a Network Information Service (NIS) environment. If this is the case and you need to use the su command to change user id, there must be a route to the NIS master at all times. In the event that a route doesnt exist and the su is attempted, the application script hangs. You can avoid this by enabling the HACMP cluster node to be an NIS slave. That way, a cluster node has the ability to access its own NIS map files to validate a user ID.Making changes to network interfacesIn some circumstances, you can use the HACMP facility to swap a network service IP address dynamically, to an active boot interface on the same node and network, without shutting down cluster services on the node.自动切换IPTypically, stop the cluster to make any change to network interfaces. If you must change the IP address of an network interface, or if you change the IP label/address, make sure to make the changes to both DNS or NIS and the /etc/hosts file. If DNS or NIS and /etc/hosts are not updated, you will be unable to synchronize the cluster nodes or do any DARE operations. If DNS or NIS services are interrupted, the /etc/hosts file is used for name resolution. You must also redo cl_setup kerberos if you are using Kerberos security.If NIS or DNS is in operation, IP lookup defaults to a nameserver system for n