<table border="1" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="background-color:#ededed; vertical-align:top; width:171px"> <p><strong>Name</strong></p> </td> <td style="background-color:#ededed; vertical-align:top; width:617px"> <p><strong>Description</strong></p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Region</p> </td> <td style="vertical-align:top; width:617px"> <p>Geographical location of an instance. A region can have multiple availability zones.</p> <p>Ping An Cloud RDS supports remote disaster recovery instances and remote read-only instances in different regions.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Availability zone</p> </td> <td style="vertical-align:top; width:617px"> <p>Independent physical area with power supplies and network. An availability zone contains one or multiple data centers.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Master availability zone</p> </td> <td style="vertical-align:top; width:617px"> <p>Availability zone of the RDS instance that is accessed by an application. It is the availability zone selected in creating an RDS instance. The RDS instance can be read and written.</p> <p>We recommend that you create an RDS instance in the same availability zone as that of the ECS host where applications locate.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Backup availability zone</p> </td> <td style="vertical-align:top; width:617px"> <p>Availability zone where the intra-city disaster recovery instance resides.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>General instance</p> </td> <td style="vertical-align:top; width:617px"> <p>An RDS instance that is created in a designated master availability zone in real time. It can be read and written and is the default instance for application access.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Disaster recovery instance</p> </td> <td style="vertical-align:top; width:617px"> <p>To improve high availability, you can switch services to an intra-city or remote disaster recovery instances to ensure normal business operation when the general instance is not available.</p> <p>A disaster recovery instance can be an intra-city one or remote one::</p> <ul> <li><strong>Intra-city DR instance</strong>&mdash;Only one intra-city DR instance exists for a general instance . The system automatically creates an intra-city DR instance for a general instance in the same region as the general instance in the maintenance time period.</li> <li><strong>Remote DR instance</strong>&mdash;Only one remote DR instance can be created in each remote region. You can manually create a remote DR instance for a general instance at any time after creating the general instance.</li> </ul> <p><img src="https://obs-cn-shanghai.yun.pingan.com/pcp-portal/20200107142932-1e785c6a943f.png" style="height:19px; margin:0px; width:90px" />: There might be a latency of data synchronization between a general instance and a DR instance.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Read-only instance</p> </td> <td style="vertical-align:top; width:617px"> <p>To reduce the reading load of general instances, you can manually create read-only instances to separate reading writing.</p> <p>1.&nbsp; Read-only instances include intra-city and remote read-only instances:</p> <ul> <li><strong>Intra-city read-only instance</strong>&mdash;Must be located in the same availability zone as the intra-city DR instance. Multiple intra-city read-only instances are supported. We recommend that you create no more than five intra-city read-only instances.</li> <li><strong>Remote read-only instance</strong>&mdash;Only one remote read-only instance can be created in a remote region.</li> </ul> <p>2.&nbsp; You can manually create read-only instances at any time after creating intra-city DR instances.</p> <p>3.&nbsp; Computing specifications upgrading, whitelist configuration and SSL encryption, parameter modification, slow-query log mana gement, restarting, and releasing of a read-only instance can be independent from that of a general instance.</p> <p>4.&nbsp; The version of a read-only instance must be identical with the version of a general instance.</p> <p><img src="https://obs-cn-shanghai.yun.pingan.com/pcp-portal/20200107142932-1e785c6a943f.png" style="height:19px; margin:0px; width:90px" />: Latency of data synchronization might exist between a general instance and a read-only instance.</p> </td> </tr> <tr> <td style="vertical-align:top; width:171px"> <p>Temporary recovery instance</p> </td> <td style="vertical-align:top; width:617px"> <p>In the process of restoring backup of database, Ping An Cloud RDS will create a temporary recovery instance in the region of the general instance. For more information about restoring backup, see <a href="http://pinganyun.com/ssr/help/database/RDS/User_Guide_RDS_MySQL.Backup_and_Restore.Restore" target="_blank">RDS MySQL</a> and <a href="http://pinganyun.com/ssr/help/database/RDS/User_Guide_RDS_PostgreSQL.Backup_and_Restore.Restore" target="_blank">RDS PostgreSQL</a>.&nbsp;</p> </td> </tr> </tbody> </table>