<p class="shortdesc">本文主要介绍如何从主实例切换至同城灾备实例。</p> <section class="section prereq" id="host__prereq_glq_hdf_hsb"><div class="tasklabel"><h2 class="doc-tairway">前提条件</h2></div> <p class="p">您已成功创建常规实例，可参考<a class="xref" href="/ssr/help/database/RASESQL/User_Guide_for_RDS_PostgreSQL.Instance_Management.Create_Instance.Create_Common_Instance_MySQL" target="_blank" rel="external noopener">创建常规实例</a>。</p> </section> <section class="section context"><div class="tasklabel"><h2 class="doc-tairway">背景信息</h2></div> <p class="p">系统容灾演练时，可使用同城容灾切换功能，切换后由同城灾备实例提供服务。</p> </section> <section class="section attention" id="host__ffx_2x2_m5b"><div class="tasklabel"><h2 class="doc-tairway">注意事项</h2></div> <ul class="ul" id="host__ul_kkx_jx2_m5b"> <li class="li"> <p class="p">常规实例主可用区发生故障时，同城容灾切换功能不可用。</p> </li> <li class="li"> <p class="p">切换至同城灾备实例后，将无法执行如下操作：</p> <ol class="ol" id="host__ol_vh2_lx2_m5b"> <li class="li"> <p class="p"> 变更实例计算规格。</p> </li> <li class="li"> <p class="p"> 释放常规实例。</p> </li> <li class="li"> <p class="p"> 重启常规实例。</p> </li> <li class="li"> <p class="p"> 创建只读实例或远程灾备实例。</p> </li> <li class="li"> <p class="p"> 开通或删除白名单。</p> </li> <li class="li"> <p class="p"> 恢复备份。</p> </li> <li class="li"> <p class="p"> 修改参数。</p> </li> </ol> </li> </ul> </section> <section><div class="tasklabel"><h2 class="doc-tairway">操作步骤</h2></div><ol class="ol steps"><li class="li step"> <span class="ph cmd"> 登录<a class="xref" href="https://www.ocftcloud.com/console/rds/instance" target="_blank" rel="external noopener">关系型数据库RASESQL管理控制台</a>。</span> </li><li class="li step"> <span class="ph cmd">单击左侧导航栏<strong class="ph b">RDS-RASESQL</strong>，进入<strong class="ph b">云数据库管理</strong>页面。</span> </li><li class="li step"> <span class="ph cmd">选择目标地域。</span> </li><li class="li step"> <span class="ph cmd">单击目标实例<strong class="ph b">操作</strong>列的<strong class="ph b">管理</strong>，选择<strong class="ph b">基本信息</strong>页签。</span> </li><li class="li step"> <span class="ph cmd">在<strong class="ph b">同城容灾切换</strong>区域，单击<strong class="ph b">同城容灾切换</strong>。</span> </li><li class="li step"> <span class="ph cmd">在<strong class="ph b">同城切换</strong>页面，单击<strong class="ph b">确定</strong>。</span> </li></ol></section> <section class="section result" id="host__result_h1d_xx2_m5b"><div class="tasklabel"><h2 class="doc-tairway">执行结果</h2></div> <ol class="ol" id="host__ol_fvd_xx2_m5b"> <li class="li">在<strong class="ph b">云数据库管理</strong>页面，目标实例<strong class="ph b">状态</strong>显示为<strong class="ph b">切换同城灾备中</strong>。</li> <li class="li">成功切换至同城灾备实例后，目标实例<strong class="ph b">状态</strong>显示为<strong class="ph b">运行中</strong>。</li> </ol> </section> <section class="section postreq" id="host__postreq_o21_yx2_m5b"><div class="tasklabel"><h2 class="doc-tairway">后续操作</h2></div> <p class="p">从主实例切换至同城灾备实例后，可根据如下说明访问RASESQL实例。</p> <ul class="ul" id="host__ul_jd3_yx2_m5b"> <li class="li">若主可用区无故障，则主实例和同城灾备实例的域名均可用，连接实例可参考<a class="xref" href="/ssr/help/database/RASESQL/Getting_Started.Connect_RDS_PostgreSQL.Linux_RASESQL" target="_blank" rel="external noopener">连接并访问RASESQL实例</a>。</li> <li class="li">若主可用区发生故障，则仅同城灾备实例的域名可用。使用同城灾备实例的域名访问时，连接端口、数据库名、用户名以及密码等信息与主实例相同。</li> </ul> </section>