图5演示了同步主系统和备用系统的HADR过程。
Figure 5 illustrates the HADR processes synchronizing a primary and standby system.
备用系统收到日志写后，将确认通知发送到主系统。
Once the standby system receives the log write, it sends acknowledgements to the primary.
而异步可用性则不保证主系统和辅助系统是完全同步的。
Asynchronous availability does not guarantee that primary and secondary system databases are completely synchronized.
在故障转移过程中，数据源从主系统移动到辅助系统。
In the failover process, the data source is moved from the primary to the secondary system.
例如，MDM系统是主系统，而事务性系统是从系统。
So for example, it could be that the MDM system is the master and the transactional systems are the slave systems.
如果主系统主机发生错误，虚拟ip地址就切换到备用机上。
In the event of a failure on the primary host, this virtual IP address fails over to the standby.
主系统执行所有事务性工作，并将任何数据库更改复制到备用系统。
The primary system performs all transactional work and replicates any database changes to the standby.
如果要创建的辅助系统与主系统的路径设置不同，这种方法非常有用。
This would be useful if creating a secondary system that has a different set of paths associated with it than the primary.
当主系统上备份的逻辑日志可用时，可以将它们恢复到辅助系统上。
Logical logs backed up on the primary system can be restored on the secondary system as they become available.
客户端使用一个虚拟ip地址，通过公共网络连接到主系统数据库。
The client connects to the primary database using the public network using a virtual IP address.
heartbeat总是优先选择主系统，只要有可能，就先从那里开始运行。
Heartbeat will always give preference to the primary system and will start to run there if possible.
当主系统出故障时，连续日志恢复特性使一个辅助系统可用，以替代主系统。
In case the primary system fails, the continuous log restore feature makes a secondary system available to replace the primary system.
系统配置支持故障转移和灾难恢复，而主系统和备份系统可以放置在距离很远的两个位置。
System configurations support failover and disaster recovery, as primary and backup systems may be separated by many miles.
一个DB 2HADR场景由两个DB 2系统组成，一个是主系统，一个是备用系统。
A DB2 HADR scenario consists of two DB2 systems, a primary and a standby.
所有的主板都包括了一小块的只读存储器rom，它与用于载入和运行软件的主系统内存分离。
All motherboards include a small piece of Read Only memory (ROM) which is separate from the main system memory used for loading and running software.
引用MDM解决方案模式：这种主数据系统设置意味着应用程序系统仍然是记录的主系统。
Referential MDM solution pattern: This setup of a master data system implies that the application systems are still the master systems of record.
典型示例是灾难恢复测试，其中涉及故障转移到热备用系统、测试应用程序，然后退回到主系统。
The classic example is a disaster recovery test, which involves failing over to a warm standby system, testing the applications, and then failing back to the primary systems.
如果主系统出故障，可以将剩下的可用逻辑日志恢复到辅助系统上，然后使后者上线，担任新的主系统。
If the primary system fails, the remaining available logical logs can be restored on the second system, which can then be brought online and function as the new primary system.
默认的复制方法(也有其他可用的方法)只要求在将确认通知返回给主系统之前，备用系统的内存中收到一个日志写。
The default replication method (others are available) only requires that a log write be received in memory at the standby before acknowledgement is returned to the primary.
将数据库从主系统移动到辅助系统的方法因情况而异，但是这个过程总会产生一个时间窗，在这个时间窗内，数据还没有完成从一个系统到另一个系统的迁移。
The method of moving database changes from the primary to the secondary system varies, but the process produces a window of time during which data has not migrated from one system to the other.
从主系统根目录导航到 /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS2.0.sdk/usr/lib/。
Navigate to /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS2.0.sdk/usr/lib/ from the main system root directory.
如果反过来，就意味着只在事务性系统中修改主数据，而MDM系统是只读的。
If it's the other way round, this means that master data is changed only in the transactional systems and the MDM system is read only.
诺斯罗普·格鲁曼公司作为系统主承包商，于1996年6月获得AMDWS的第一份合同。
Northrop Grumman, the prime contractor for the system, was awarded the first AMDWS contract in June 1996.
通常情况下，业务系统用户通过各自的业务系统更新和查询主数据。
Business system users update and query master data typically through the use of their respective business systems.
使用MDM系统提供主数据对象的完整视图，但是不需要把所有信息都保存在MDM系统本身中。
MDM systems are used to provide a complete view of a master data object without persisting all of the information within the MDM system itself.
然而，这是一种笨拙的权宜之计，会导致一些问题。比如，安装多个操作系统时，如果过多的操作系统要求自身拥有过多的主分区，就会出现困难。
This is, however, an ugly workaround that creates its own problems, such as difficulties installing multiple operating systems when too many of them want too many primary partitions to themselves.
基本上，PersistenceManager是JDO持久性系统的主接口。
Essentially, PersistenceManager is the main interface to the JDO persistence system.
此外，输入测试数据的创建是通过对来自在测系统的主数据的自动导入来加速的。
Additionally, the creation of input test data is accelerated through automatic importing of master data from the system under test.
在这个层次，运行第二个HDFS实例(使用单独的名字节点)，作为热备份——如果主HDFS宕机，系统将向备份的HDFS写入。
In this layer, they also run a second HDFS installation (with a separate name node), which acts as a hot standy - if the primary HDFS is down, the system writes to the backup HDFS.
遗憾的是，许多需要主分区的操作系统都不能从GPT磁盘引导。
Unfortunately, many of the operating systems that require primary partitions are unable to boot from GPT disks.
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