RAC 特定引數設定

除了例項和執行緒引數外,還有一些在RAC環境中有特殊意義的引數:

Cluster_Database

Cluster_Interconnects

Active_Instance_Count

Max_Commit_Propagation_Delay

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cluster_database 決定著控制檔案是否要在共享模式下安裝,大多數情況下必須將此值設定為true;升級打補丁時所有例項必須關閉,且只有該例項被開啟並將cluster_database設定為false;升級指令碼通常在startup migrate 命令之後執行;另外情況是資料庫要設定成歸檔日誌模式或閃回模式時必須將所有例項關閉後將cluster_database設定為false;然後才能startup mount 設定alter database archivelog

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

cluster_interconnects 用於指定叢集中的IPC通訊網路;在修改cluster_interconnects時必須對每個例項都進行修改,像下面這樣指定例項名:

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';

指定兩個IP地址可以在中間加上冒號

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命令檢查互連情況,首先必須加入pid

SQL> oradebug setmypid

statement processed

SQL>oradebug ipc

Information written to trace file

admno 0x4169a831 admport:
SSKGXPT 0x1044acb0 flags SSKGXPT_READPENDING socket no 7 IP 10.0.0.2 UDP 33381
context timestamp 0x36
no ports
sconno accono ertt state seq# sent async sync rtrans acks
0x65b62428 0x7589e9e0 32 3 32766 3 3 0 0 3
0x65b62429 0x3aff8b50 32 3 32764 1 1 0 0 1

在udump 查詢跟蹤檔案有顯示IP字樣

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active_instance_count 該引數最好設定為叢集中例項的總數

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

max_commit_propagation_delay定義本地例項的SGA中系統變更號(system change number,SCN)在被LGWR程式重新整理之前保持的最長時間,預設設定為700(7秒);如果置0 會看到Lamport方案被選中,會增加網路上的訊息通訊量,對效能造成輕微影響