zoukankan      html  css  js  c++  java
  • 052-229(新增70题2018)

    Redo log files are multiplexed in your database. The disk in which you have one of the redo log members is highly fragmented. In the process of defragmentation you lose the redo log member, which is not a member of the current group.

    How would you recover from the loss of the redo log member?

    A. SMON would automatically restore the lost file.

    B. You would need to restore the whole database from the last backup.

    C. You would need to restore the file from the last full database backup.

    D. You would need to use flashback technology to restore the lost redo log member.

    E. You would need to use Recovery Manager (RMAN) to restore the lost redo log member.

    F. You would need to restore the missing log file by copying one of the remaining files from the same group.

    Answer: F

    Multiplexing Redo Log Files

    To protect against a failure involving the redo log itself, Oracle Database allows a multiplexed redo log, meaning that two or more identical copies of the redo log can be automatically maintained in separate locations. For the most benefit, these locations should be on separate disks. Even if all copies of the redo log are on the same disk, however, the redundancy can help protect against I/O errors, file corruption, and so on. When redo log files are multiplexed, LGWR concurrently writes the same redo log information to multiple identical redo log files, thereby eliminating a single point of redo log failure.

    Multiplexing is implemented by creating groups of redo log files. A group consists of a redo log file and its multiplexed copies. Each identical copy is said to be a member of the group. Each redo log group is defined by a number, such as group 1, group 2, and so on.

  • 相关阅读:
    docker系列五之数据卷(volumn)
    docker系列四之docker镜像与容器的常用命令
    docker系列三之docker的安装
    Docker系列之入门
    idea Maven 插件 docker-maven-plugin 打包docker镜像上传到远程仓库
    mysql5.7 主从配置
    docker 私有仓库搭建
    PowerDesigner 把Comment复制到name中和把name复制到Comment
    docker 常用指令
    jenkins+gitlab+maven+docker自动化部署spring boot
  • 原文地址:https://www.cnblogs.com/Babylon/p/8621572.html
Copyright © 2011-2022 走看看