【翻譯自mos文章】設定了RemoveIPC=yes 的RHEL7.2上 會crash掉Oracle asm 執行個體和Oracle database執行個體

標籤：

設定了RemoveIPC=yes 的RHEL7.2  會crash掉Oracle asm 執行個體和Oracle database執行個體，該問題也會在使用Shared Memory Segment (SHM) or Semaphores (SEM)的應用程式中發生。
來源於：
ALERT: Setting RemoveIPC=yes on Redhat 7.2 Crashes ASM and Database Instances as Well as Any Application That Uses a Shared Memory Segment (SHM) or Semaphores (SEM) (文檔 ID 2081410.1)

適用於：
Oracle Database - Standard Edition
Oracle Database - Enterprise Edition
Linux x86-64
Linux x86

描述：
在RHEL7.2中，systemd-logind 服務引入了一個新特性，該新特性是：當一個user 完全退出os之後，remove掉所有的IPC objects。
該特性由/etc/systemd/logind.conf參數檔案中RemoveIPC選項來控制。詳細請看man logind.conf(5)

在RHEL7.2中，RemoveIPC的預設值為yes

因此，當最後一個oracle 或者Grid使用者退出時，作業系統會remove 掉這個user的shared memory segments and semaphores

由於Oracle ASM 和database 使用 shared memory segments ，remove shared memory segments將會crash掉Oracle ASM and database  instances.

請參考Redhat bug 1264533  - https://bugzilla.redhat.com/show_bug.cgi?id=1264533

 

OCCURRENCE（不知道翻譯成什麼比較合適）
該問題影響使用the shared memory segments 和semaphores 的所有應用程式,因此，Oracle ASM 執行個體和Oracle Database 執行個體均受到影響。

Oracle Linux 7.2 通過在/etc/systemd/logind.conf設定檔中明確設定RemoveIPC為no，Oracle Linux7.2 避免了該問題，
但是若是/etc/systemd/logind.conf檔案是在os upgrade之前修改的，那麼yum/update將會寫一個正確的設定檔（RemoveIPC=no），該設定檔名是logind.conf.rpmnew，如果使用者使用原來的設定檔，那麼本文描述的failures將會發生。
為了避免本問題，當os升級之後，務必編輯logind.conf 檔案並設定RemoveIPC=no。這在Oracle Linux 7.2 release notes中有記錄。

 

癥狀：

1) Installing 11.2 and 12c GI/CRS fails, because ASM crashes towards the end of the installation.2) Upgrading to 11.2 and 12c GI/CRS fails.3) After Redhat Linux is upgraded to 7.2, 11.2 and 12c ASM and database instances crash.

systemd-logind remove掉IPC objects可能在任何時候發生，故障的表現可以有很大的不同，下面是故障的幾個例子

Most common error that occurs is that the following is found in the asm or database alert.log:ORA-27157: OS post/wait facility removedORA-27300: OS system dependent operation:semop failed with status: 43ORA-27301: OS failure message: Identifier removedORA-27302: failure occurred at: sskgpwwait1

The second observed error occurs during installation and upgrade when asmca fails with the following error:KFOD-00313: No ASM instances available. CSS group services were successfully initilized by kgxgncinKFOD-00105: Could not open pfile '[email protected]'

The third observed error occurred during installation and upgrade:Creation of ASM password file failed. Following error occurred: Error in Process: /u01/app/12.1.0/grid/bin/orapwd Enter password for SYS:OPW-00009: Could not establish connection to Automatic Storage Management instance2015/11/20 21:38:45 CLSRSC-184: Configuration of ASM failed2015/11/20 21:38:46 CLSRSC-258: Failed to configure and start ASM

The fourth observed error is the following message is found in the /var/log/messages file around the time that asm or database instance crashed:Nov 20 21:38:43 testc201 kernel: traps: oracle[24861] trap divide errorip:3896db8 sp:7ffef1de3c40 error:0 in oracle[400000+ef57000]

 

變通的解決方案：
1) Set RemoveIPC=no in /etc/systemd/logind.conf

2) Reboot the server or restart systemd-logind as follows:
    # systemctl daemon-reload
    # systemctl restart systemd-logind

補丁：
從RHEL7.2遷移到Oracle Linux7.2可以解決本問題。
若是遷移到Oracle Linux7.2不可能，請使用上述變通的解決方案

 

曆史：
2015年11月23日，本文章被建立。

【翻譯自mos文章】設定了RemoveIPC=yes 的RHEL7.2上 會crash掉Oracle asm 執行個體和Oracle database執行個體