RAC 特定参数设置

 

除了实例和线程参数外,还有一些在RAC环境中有特殊意义的参数:

Cluster_Database

Cluster_Interconnects

Active_Instance_Count

Max_Commit_Propagation_Delay

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

cluster_database 决定着控制文件是否要在共享模式下安装,大多数情况下必须将此值设置为true;升级打补丁时所有实例必须关闭,且只有该实例被打开并将cluster_database设置为false;升级脚本通常在startup migrate 命令之后运行;另外情况是数据库要设置成归档日志模式或闪回模式时必须将所有实例关闭后将cluster_database设置为false;然后才能startup mount 设置alter database archivelog

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

cluster_interconnects 用于指定集群中的IPC通信网络;在修改cluster_interconnects时必须对每个实例都进行修改,像下面这样指定实例名:

alter system set cluster_interconnects = '192.168.1.25' scope = spfile sid = 'grid1';

alter system set cluster_interconnects = '192.168.1.26' scope = spfile sid = 'grid2';

指定两个IP地址可以在中间加上冒号

alter system set cluster_interconnects = '10.1.1.11:192.168.1.25' scope = spfile sid = 'grid2';

alter system set cluster_interconnects = '10.1.1.12:192.168.1.26' scope = spfile sid = 'grid2';

在sqlplus 中用oradebug ipc命令检查互连情况,首先必须加入pid

SQL> oradebug setmypid

statement processed

SQL>oradebug ipc

Information written to trace file

wait delta 350 sec (350302 msec) ctx ts 0x4b6fb last ts 0x231a
user cpu time since last wait 0 sec 0 ticks
system cpu time since last wait 0 sec 0 ticks
locked 1
blocked 0
timed wait receives 0
admno 0x28e4e034 admport:
SSKGXPT 0x64f06fc flags SSKGXPT_READPENDING     info for network 0
        socket no 7     IP 1.1.1.2      UDP 28499
        sflags SSKGXPT_UP
        info for network 1
        socket no 0     IP 0.0.0.0      UDP 0
        sflags SSKGXPT_DOWN
        active 0        actcnt 1
context timestamp 0x4b6fb
        no ports
    sconno     accono   ertt  state   seq#   sent  async   sync rtrans   acks
0x6643af6f 0x785672e0     32      3 180388659196      1      1      0      0 180388626433

在udump 查找跟踪文件有显示IP字样

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

active_instance_count 该参数最好设置为集群中实例的总数

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

max_commit_propagation_delay定义本地实例的SGA中系统变更号(system change number,SCN)在被LGWR进程刷新之前保持的最长时间,默认设置为700(7秒);如果置0 会看到Lamport方案被选中,会增加网络上的消息通信量,对性能造成轻微影响