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EMC's ControlCenter server runs a master agent that manages and communicates with storage-specific agents over TCP/IP and can run on a Unix, Windows or a mainframe system MVS host. These client agents are responsible for managing the storage elements that are assigned to them for control and management by the master agent. Management tasks consist of data collection, status monitoring and command execution on the storage element. A nice management feature of ECC is that you can install and upgrade client agents from the server, which reduces the overall management effort of the solution.
Client agents receive their policies via the server, after which they are stored locally to reduce the dependency on the server. Secondary agents that run on a separate host can be configured to support the primary agents should the hosting server fail. While most of us would be happy to get a single pair of eyes into our storage infrastructures, having redundancy at this level is a bonus because it comes with no additional cost.
Policies control the polling frequency of the storage element by the client agent raising threshold alerts and status events to the operator. Once a violation has been detected, you have the option of autocorrecting the violation or simply raising the event to an operator's attention and possible action. ECC's autocorrection feature is available with the Automated Resource Manager (ARM) add-on and implemented with scripting, which gives the user more flexibility in their approach to policy management.
Also included with ARM is ECC's reporting feature. This gives the user the ability to create and run reports against the repository either manually or on a predefined schedule. Additionally, the Workload Analyzer has the ability to collect, archive and report on historical performance from the host or Symmetrix point of view.
That delivers the immediate benefit of having the ability to see how network utilization is rising over time. If, for example, you are administering an application with predictable inter-switch link (ISL) usage, and then add an additional application (initiator) to feed traffic over the same ISL, you can determine at which point the network traffic of the initial application(s) starts to degrade. Without this historic feature, ISL congestion that occurs in the middle of the night wouldn't be noticeable, especially if the workload is completed in a timely fashion. This is a classic example of ISL oversubscription, which saves budget capital in the initial design of the SAN. However, the oversubscription ratio is at best an educated guess and shouldn't be considered reality. With Workload Analyzer, you can determine the exact point at which an E_Port is throttled.
The repository is a relational database that's modeled after RAB1 (.dbm flat file) data structures and was reportedly chosen to eliminate the need for staff with DBA skills. The repository contains configuration data, status, utilization and capacity data for storage elements in the SAN. This data represents both current and historical data provides the raw functionality for point-in-time report generation. In addition to the GUI, the user can access data elements in the repository using SQL or XML.
ECC's repository is populated by store(s) that convert incoming data from the storage-specific agents. Conversions are performed by specific plug-ins that process the different types of data coming from the managed agents. While processing the data, the store(s) can also notify the consoles of the changing events in the SAN, updating and correcting visual links between resources. There can be more than one store available for allocation to an agent sending data to the repository. Allocation occurs dynamically and is based on load and availability of the store(s) in the environment. Again, adding scalability and availability to the solution.
Storage-specific agents run on hosts (i.e., Unix, Windows, MVS) that have access to the storage elements that they're managing. And although these agents support non-EMC hardware and software, the functionality of these agents depends on the particular vendor's willingness to share its product's intelligence. As for disk arrays, with the exception of Hewlett-Packard's StorageWorks line of products, don't look for the same functional abilities for non-EMC hardware as you would for EMC hardware. To ensure that you actually get the functionality you need, check with EMC for interoperability, and put pressure on your other vendors to share the intelligence of their products. Of course, this is contradictory to patent holdings and market share, but how else are we to manage heterogeneous storage environments with any hope of reducing the reported 7:1 expense regarding management to hardware ratio?
This was first published in June 2003