Now that we understand the architecture and components that are used in the different consolidation models, let’s examine some standard deployment issues that need to be addressed. These include security, operational, resource and fault isolation issues as well as scalability and high availability. It is very important to understand that delivery services and the SLAs around those services will drive the actual architecture, design, and implementation. Therefore, architecture, design, and implementation also play directly into the chargeback and metering aspect of the services.
Security isolation is often the first point that management worries about in any cloud model. Is my data safe? What options do I have for securing my consolidated infrastructure? How can I prevent the cloud database administrator from accessing and viewing my data? How can I ensure that my network traffic is secure? Can I ensure I meet compliance regulations?
With all of these questions, security isolation has become an essential component of any cloud deployment. Security breaches can arise not only externally but also internally, so all aspects of your cloud infrastructure must be secure.
Operational isolation in a DBaaS cloud requires that any maintenance being performed on a database or on the environment the database operates in affects the smallest number of other databases in the same pool. Meeting this requirement clearly becomes more problematic for operating system or grid infrastructure maintenance, though the impact can be minimized by rolling upgrades where allowed. Isolation for patching an Oracle database kernel can be provided by minimizing the number of databases per Oracle home, but adding Oracle homes also increases management overheads. Database startup and shutdown would normally be considered database-dependent operations, but administrative errors such as setting the wrong
ORACLE_SID can lead to unforeseen impacts on other databases. Again, isolation can be provided at the
ORACLE_HOME level and by having different user IDs and group IDs at the kernel level, but this also leads to more management overhead, and, it must be said, more likelihood of human error.
In a DBaaS cloud, resource isolation deals with the allocation and segregation of resources such as CPU, memory, network (public and private), and storage (I/O per second and overall capacity). Management concerns include questions such as How does the CPU usage of my database affect other databases in the DBaaS cloud? How much memory should I allocate to a specific database? Can I restrict the network utilization, both at the public network and interconnect levels, to not impact other databases? Likewise, how can I guarantee storage capacity and IOPS for my databases?
Fault isolation in a DBaaS cloud is normally provided at the database level, since that is the unit of granularity in the multitenant architecture. Each database and its associated instance (or instances, in RAC environments) need to be isolated from other databases. Even when all databases are run from a single
ORACLE_HOME, database faults are normally isolated to a failing instance, so fault isolation is maintained by fencing off the offending instance. However, other failures may require handling at different levels. For example, concerns include how to deal with a server, network, or storage failure. Such failures are normally handled by some form of redundancy such as multinode setups, active/passive switches, bonded networks, or redundant storage such as Automatic Storage Management (ASM) redundancy.
Scalability is a fundamental characteristic of DBaaS architectures by virtue of their support for self-service, elasticity, and multitenancy. Oracle’s database technologies provide a number of ways to support scalability when delivering database services, including resource management and quality of service, addition of extra storage through such functionality such as multiple Exadata Database Machine frames, horizontal scaling via RACs when service demands increase beyond the capabilities of a single machine, and scalable management resources where Oracle Enterprise Manager can add management nodes as the number of targets under management grows.
DBaaS High Availability
Not all consumers require the same level of availability in a cloud environment. Oracle’s DBaaS self-service catalog allows the capability to include different levels of availability using a metals model, as shown in Table 1.
For example, the bronze standard provides a single-instance database service (possibly via RAC One Node), whereas the other extreme, platinum, would normally include a RAC database with multiple standbys. These standbys might include a near standby in the same data center as your RAC database and a far standby in a completely separate remote data center. These measures help to improve the high-availability and disaster recovery goals you have for that database. In Oracle Enterprise Manager 188.8.131.52, with the added support for Data Guard, you now have the ability with just a few clicks to provision the primary and multiple standbys across different data centers. The standbys can be either single instance or a RAC configuration.