Oracle ASM Filter Driver

    Oracle ASM Filter Driver(asmfd) 是oracle 12c  gi 开始提供的一个内核模块位于oracle asm disk io 请求路径之中，asmfd 屏蔽任何非oracle 产生的io 写请求，降低了oracle asm 磁盘由于意外覆写导致的数据丢失风险，简化了oracle asm 磁盘权限与名称固定所需的一系列配置，用于取代asmlib 以及udev 手动编写规则文件。asmfd 也减少了asm 用于数据库io所需的文件描述符，降低了os 资源消耗。

      Oracle asmfd 主要支持Linux、Solaris 2种操作系统平台，部署之前需确保操作系统以及内核版本在受支持范围之内:

    这里以oracle linux 8.6、oracle database 19c为例实施asmfd：

    1、首先部署好gi、db软件环境，确保更新补丁至最新。

         如没有更新补丁，配置asmfd 会出现如下不支持错误:

         ASMCMD-9520: AFD is not 'supported'

    2、配置asm filter driver。

       a、 首先确保oracle restart 或clusterware 服务处于停止状态：

        oracle restart 停止has:

        # /u01/app/19.3.0/grid/bin/crsctl stop has

        oracle clusterware 停止crs:

        # /u01/app/19.3.0/grid/bin/crsctl stop crs -all

       b、以root 账号配置asmfd: 

[root@zjg-dba-bidbdr ~]# export ORACLE_HOME=/u01/app/19.3.0/grid/
[root@zjg-dba-bidbdr ~]# export ORACLE_BASE=/tmp
[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/asmcmd afd_configure

AFD-627: AFD distribution files found.
AFD-634: Removing previous AFD installation.
AFD-635: Previous AFD components successfully removed.
AFD-9294: updating file /etc/sysconfig/oracledrivers.conf
AFD-636: Installing requested AFD software.
AFD-637: Loading installed AFD drivers.
AFD-9321: Creating udev for AFD.
AFD-9323: Creating module dependencies - this may take some time.
AFD-9154: Loading 'oracleafd.ko' driver.
AFD-649: Verifying AFD devices.
AFD-9156: Detecting control device '/dev/oracleafd/admin'.
AFD-638: AFD installation correctness verified.
Modifying resource dependencies - this may take some time.

[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/asmcmd afd_state
ASMCMD-9526: The AFD state is 'LOADED' and filtering is 'ENABLED' on host 'zjg-dba-bidbdr'

  asmfd 配置好后，会在/etc/udev/rules.d 目录下产生udev规则文件53-afd.rules，内容如下：

#
# AFD devices
KERNEL=="oracleafd/.*", OWNER="grid", GROUP="asmadmin", MODE="0770"
KERNEL=="oracleafd/*", OWNER="grid", GROUP="asmadmin", MODE="0770"
KERNEL=="oracleafd/disks/*", OWNER="grid", GROUP="asmadmin", MODE="0660"

   c、如要移除asmfd，需确保has、crs 服务堆栈处于关闭状态，以root账号执行:

[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/acfsload stop
[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/asmcmd afd_deconfigure
AFD-632: Existing AFD installation detected.
AFD-634: Removing previous AFD installation.
AFD-635: Previous AFD components successfully removed.
Modifying resource dependencies - this may take some time.

   d、标识asm 磁盘:

[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/asmcmd afd_label data1 /dev/sdb

[root@zjg-dba-bidbdr ~]# /u01/app/19.3.0/grid/bin/asmcmd afd_lslbl /dev/sdb
--------------------------------------------------------------------------------
Label                     Duplicate  Path
================================================================================
DATA1                                 /dev/sdb

e、确保has、crs 服务堆栈处于启动状态，以grid 用户执行asmca 创建asm 实例以及磁盘组: