RAC連接高可用特性楊廷琨RAC連接高可用技術(shù)概述負(fù)載均衡LOAD_BALANCE靜態(tài)FAILOVER動(dòng)態(tài)FAILOVER高可用連接——LOAD_BALANCE啟用：監(jiān)聽根據(jù)各個(gè)節(jié)點(diǎn)上建立連接的數(shù)量，將新連接分配到連接上的實(shí)例禁用：只連接地址列表中的第一個(gè)地址高可用連接——LOAD_BALANCE初始化參數(shù)REMOTE_LISTENERtnsnames.ora中配置LOAD_BALANCE應(yīng)用范圍：DESCRIPTION_LIST、DESCRIPTION、ADDRESS_LIST默認(rèn)值：在DESCRIPTION為ON高可用連接——LOAD_BALANCETESTRAC=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.224)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.225)(PORT=1521))(LOAD_BALANCE=ON))(CONNECT_DATA=(SERVICE_NAME=TESTRAC)))高可用連接——LOAD_BALANCE限制：只對(duì)通過監(jiān)聽建立的連接有效考慮數(shù)量而不考慮節(jié)點(diǎn)的忙閑高可用連接——靜態(tài)FAILOVER啟用：當(dāng)?shù)谝粋€(gè)地址連接失敗自動(dòng)嘗試連接其他地址禁用：當(dāng)?shù)谝粋€(gè)地址連接失敗時(shí)報(bào)錯(cuò)高可用連接——靜態(tài)FAILOVER初始化參數(shù)REMOTE_LISTENERtnsnames.ora中配置FAILOVER應(yīng)用范圍：DESCRIPTION_LIST、DESCRIPTION、ADDRESS_LIST默認(rèn)值：在DESCRIPTION_LIST、DESCRIPTION、ADDRESS_LIST為ON高可用連接——靜態(tài)FAILOVERTESTRAC=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.224)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.225)(PORT=1521))(FAILOVER=ON))(CONNECT_DATA=(SERVICE_NAME=TESTRAC)))高可用連接——?jiǎng)討B(tài)FAILOVER啟用：會(huì)話所在實(shí)例崩潰后自動(dòng)切換到BACKUP對(duì)應(yīng)的實(shí)例禁用：會(huì)話所在實(shí)例崩潰后報(bào)錯(cuò)高可用連接——?jiǎng)討B(tài)FAILOVERtnsnames.ora中設(shè)置FAILOVER_MODETYPE：SESSIONSELECTNONEMETHOD：BASICPRECONNECTBACKUP高可用連接——?jiǎng)討B(tài)FAILOVERTESTRAC2=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.225)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=TESTRAC)(INSTANCE_NAME=TESTRAC2)

(FAILOVER_MODE=(TYPE=SELECT)(METHOD=BASIC)(BACKUP=TESTRAC1))))高可用連接——?jiǎng)討B(tài)FAILOVER限制動(dòng)態(tài)FAILOVER對(duì)于DML無效PRECONNECT方式有更好的動(dòng)態(tài)切換性能，但是會(huì)導(dǎo)致額外的性能開銷高可用連接——警惕默認(rèn)值FAILOVERLOAD_BALANCE不要依賴默認(rèn)值高可用連接——警惕FAILOVER和LOAD_BALANCE搭配不當(dāng)TESTRAC=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.224)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.225)(PORT=1521))(LOAD_BALANCE=ON)(FAILOVER=OFF))(CONNECT_DATA=(SERVICE_NAME=TESTRAC)))高可用連接——警惕連接指定實(shí)例TESTRAC1=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.224)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=TESTRAC)(INSTANCE_NAME=TESTRAC1)))高可用連接——警惕拼寫檢查SERVICE_NAME=>SERVER_NAMEINSTANCE_NAME=>INSTNACE_NAME高可用連接——警惕生效區(qū)間TESTRAC=(DESCRIPTION=

(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=172.25.198.224)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(H