最全的最经典的oracle RAC-ASM优势总结.ppt

ASM: General Architecture To use ASM, you must start a special instance called an ASM instance before you start your database instance. ASM instances do not mount databases, but instead manage the metadata needed to make ASM files available to ordinary database instances. Both ASM instances and database instances have access to a common set of disks called disk groups. Database instances access the contents of ASM files directly, communicating with an ASM instance only to get information about the layout of these files. An ASM instance contains two new background processes. One coordinates rebalance activity for disk groups. It is called RBAL. The second one performs the actual rebalance data extent movements. There can be many of these at a time, and they are called ARB0, ARB1, and so forth. An ASM instance also has most of the same background processes as a database instance (SMON, PMON, LGWR, and so on). Each database instance using ASM has two new background processes called ASMB and RBAL. RBAL performs global opens of the disks in the disk groups. At database instance startup, ASMB connects as a foreground process into the ASM instance. All communication between the database and the ASM instance is performed via this bridge. This includes physical file changes such as data file creation and deletion. Over this connection, periodic messages are exchanged to update statistics and to verify that both instances are healthy. * 1 * * * 最全的最经典的oracle RAC/ASM优势总结 Oracle Real Application Clusters 内容安排 什么是 Real Application Clusters? RAC架构组成 Rac的优势与劣势 什么是ASM ASM的优势 ASM的组成 什么是Rac Real Application Clusters 实时应用集群 为什么采用集群数据库技术？ Rac的优势与劣势 优势 高伸缩性 高可扩展性 高可用性 性能提升 缺点 数据保护的薄弱 资源竞争 网络要求高 Oracle RAC的配置结构 集群数据库服务器 镜像磁盘系统 高速交换机 / 内部高速连接(Interconnect) 交换机/光纤通道 Network 集中管理 控制台 存储区域网-SAN 低传递时间的内部连接 VIA / 专用连接 推动和利用业界 集群技术的进展 用户 无单点故障 Rac数据库文件的存储 Rac的存储结构 Rac架构的组成 Rac实例 Rac DB文件 2台以上的主机 共享存储 集群软件 共用网络与私有网络 Rac网络环境 RAC 要求每个节点必须连接到一个私有网络，用于 Clusterware 之间进行内部通讯。 RAC 要求用于内部通讯的私有网络