ORA-15055 ASM Diskgroup Status Showing Dismounted From RDBMS Instance

在資料庫例項中檢查asm 磁碟組的狀態時，顯示 DISMOUNTED,但是在asm 例項上卻顯示MOUNTED
在資料庫例項的alert 日誌中會出現如下資訊：

SUCCESS: diskgroup ASMDISK02 was mounted
SUCCESS: diskgroup ASMDISK02 was dismounted
SUCCESS: diskgroup ASMDISK02 was mounted
SUCCESS: diskgroup ASMDISK02 was dismounted
SUCCESS: diskgroup ASMDISK02 was mounted

ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '+ASMDISK01/cnf2/redo01.log'
ORA-17503: ksfdopn:2 Failed to open file +ASMDISK01/cnf2/redo01.log
ORA-15055: unable to connect to ASM instance
ORA-00020: maximum number of processes () exceeded
ORA-15055: unable to connect to ASM instance
ORA-00020: maximum number of processes () exceeded
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '+ASMDISK01/cnf2/redo01.log'
ORA-17503: ksfdopn:2 Failed to open file +ASMDISK01/cnf2/redo01.log
ORA-12549: TNS:operating system resource quota exceeded

原因：
這個問題是由於資料庫例項不能和asm 例項進行通訊，不管何時嘗試連線asm，它都用盡os 資源。在系統級別上不能建立新的程式。
在 資料庫例項上檢查磁碟組的狀態：
SQL > select name,state from v$asm_diskgroup;

NAME                                  STATE
------------------------------    -----------
ASMDISK01                       CONNECTED
ASMDISK02                       DISMOUNTED

CONNECTED 意味著資料庫例項正在使用這個磁碟組
DISMOUNTED 意味著資料庫例項將磁碟組視為不可用。

解決辦法：
在這種情況下由於asm 程式數已經達到上限，新的asm程式不能建立導致資料庫例項不能夠連線到asm上。預設的ASM程式數為40，可以將 程式相關的引數設定為更高一些 比如150