Oracle的load_balance和failover

女爷i 2022-06-18 10:38 126阅读 0赞

jdbc:oracle:thin:@  
 (description=(TRANSPORT\_CONNECT\_TIMEOUT=1)  
  (address\_list=(load\_balance=off)(failover=on)  
   (address=(protocol=tcp)(host=RAC1-vip)(port=1521))  
   (address=(protocol=tcp)(host=RAC2-vip)(port=1521))  
   (address=(protocol=tcp)(host=RAC3-vip)(port=1521)))  
  (connect\_data=(service\_name=orcl)(failover\_mode=(type=select)(method=basic)))  
 )

LOAD\_BALANCE=OFF，客户端进程首先会尝试连接 RAC1-vip，如果连不上，则会尝试RAC2-vip，如果再连不上就尝试RAC3-vip。如果设置为ON则会随机的选择一个做均衡负载。LOAD\_BALANCE =on负载均衡,FAILOVER = on 失败自动切换,这两个参数是搭配在一起的。

**LOAD\_BALANCE  
Purpose**  
To enable or disable client load balancing for multiple protocol addresses.  
When you set the parameter to on, yes, or true, Oracle Net progresses the list of addresses in a random sequence, balancing the load on the various listener or Oracle Connection Manager protocol addresses. When you set the parameter to off, no, or false, Oracle Net tries the first address in the address list. If the connection fails and the failover parameter is enabled, then Oracle Net tries the addresses sequentially until one succeeds.  
Put this parameter under either the DESCRIPTION\_LIST parameter, the DESCRIPTION parameter, or the ADDRESS\_LIST parameter.  
**Default**  
on for DESCRIPTION\_LIST  
**Values**  
yes | on | true  
no | off | false  
**Example**  
net\_service\_name=  
 (DESCRIPTION=   
  (LOAD\_BALANCE=on)  
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales1-svr)(PORT=1521))  
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales2-svr)(PORT=1521)))  
  (CONNECT\_DATA=(SERVICE\_NAME=sales.us.example.com))  
  
**FAILOVER  
Purpose**  
To enable or disable connect-time failover for multiple protocol addresses.  
When you set the parameter to on, yes, or true, Oracle Net, at connect time, fails over to a different address if the first protocol address fails. When you set the parameter to off, no, or false, Oracle Net tries one protocol address.  
Put this parameter under the DESCRIPTION\_LIST parameter, the DESCRIPTION parameter, or the ADDRESS\_LIST parameter.  
**Default**  
on for DESCRIPTION\_LIST, DESCRIPTION, and ADDRESS\_LIST.  
**Values**  
yes | on | true  
no | off | false  
**Example**  
net\_service\_name=  
 (DESCRIPTION=   
  (FAILOVER=on)  
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales1-svr)(PORT=1521))  
  (ADDRESS=(PROTOCOL=tcp)(HOST=sales2-svr)(PORT=1521)))  
  (CONNECT\_DATA=(SERVICE\_NAME=sales.us.example.com)))