Configuration of EMCPvMeVolumeTest

A volume is a logical subdivision of a vdisk, and can be mapped to controller host ports for access by hosts. A mapped volume provides the storage for a file system partition you create with your operating system or third-party tools. The storage system presents only volumes, not vdisks, to hosts. This is why, if a single volume in the EMC PowerVault ME storage system is unable to process I/O requests from hosts quickly, it can rupture the user experience with the entire storage system. Therefore, to improve fault tolerance and I/O performance of a volume, you can set cache options for individual volumes. A well-tuned cache can go a long way in reducing direct volume accesses and related I/O processing overheads. In the absence of such a cache, processing slowdowns become inevitable! In times of heavy load, weak load-balancing algorithms can aggravate the slowdown, thereby adversely impacting the user experience with the storage system. To avoid this, administrators need to continuously monitor the I/O load, the processing ability, and the cache usage of every volume in the storage system, proactively detect an I/O processing latency, rapidly determine the exact cause of the poor I/O performance - is it an improperly configured cache? Or an ineffective load-balancing engine? Or both? - and promptly initiate measures to rectify the root-cause, so that normalcy of operations can be restored. This is where the EMCPvMeVolumeTest helps.

This test auto-discovers the volumes in the storage system and reports how well each volume handles the I/O requests it receives. In addition, the test also focuses on the cache usage of every volume from time to time, and reveals whether/not any cache has been grossly under-utilized. This way, the test turns the spotlight on volumes that are experiencing a slowdown and also reveals what is causing the slowdown - load-balancing irregularities across volumes or badly configured caches?

The default parameters associated with this test are:

• The TEST PERIOD list box helps the user to decide how often this test needs to be executed.

• In the HOST text box, specify the HOST for which this test is to be configured. Since the storage device is managed using the IP address of its storage controller, the same will be displayed as host. In case of a dual-controller configuration, the IP address of the primary controller will be displayed here.

• Specify the port number at which the specified host listens in the PORT text box. By default, this is NULL.

• By default, this test always connects to the Host to collect metrics. If the Host is unavailable, then the test will not be able to execute. This is because, the Additional Controller IP is set to none by default.

  If the monitored storage device has two controllers, then you can configure the test to connect to an alternate controller, if the host is unreachable. For this purpose, specify the IP address of the alternate controller in the Additional Controller IP text box.

• In order to monitor a EMC PowerVault ME storage system, the eG agent has to be configured with the credentials of a user who has been assigned the Monitor role. Specify the login credentials of such a user in the USER and PASSWORD text boxes. To know how to create such a user, refer to Pre-requisites-for-monitoring-the-EMC PowerVault-ME-storage-system. Confirm the password by retyping it in CONFIRM PASSWORD text box.

• The Management Controller of the EMC PowerVault ME storage system provides access for monitoring and management via the HTTP and HTTPS protocols for XML API request/response semantics. To enable the eG agent to access the management controller, invoke the XML API commands, and collect the required metrics, you need to specify the SERVICE PORT on the controller that listens for HTTP/HTTPS requests for XML API semantics. By default, this is port 80.

• Specify the time duration for which this test should wait for a response from the storage system in the TIMEOUT text box. By default, this is 60 seconds.

• By default, EMC PowerVault ME system is not SSL-enabled. This is why, SSL flag is set to False by default. If it is SSL-enabled, then change this flag to True.

• If multiple components of the same component type are awaiting configuration, then an APPLY TO OTHER COMPONENTS button will appear in this page. Clicking on this button will allow you to apply the configuration to all/selected components of that type.

• Once the necessary values have been provided, clicking on the UPDATE button will register the changes made.

When changing the configuration for specific servers, a “*” beside the text box corresponding to the parameter signifies that these values have to be manually configured by the user. The parameter values that require to be configured will typically be prefixed with a “$” or contain a series of “*”. A value of “none” in the parameter value indicates that the corresponding parameter value can be changed if required.