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Configuration of OSMemoryTest
Memory shortage on a host can affect the memory allocation to crucial processes that are being executed on the target host, which in turn can adversely impact the performance of the applications running on the target host. One of the primary reasons for Memory shortage is that of precious memory space being unnecessarily hogged by Modified and Standby memory lists that hold temporary/unused data. The Modified and Standby memory lists cache temporary data when the applications/services run in the target host. These temporary data will no longer be used by the applications/services thus hogging memory space unnecessarily. Therefore, administrators should clear the cached data on a regular basis. If the cached data is not cleared regularly, sometimes, you may not be able to allocate memory to the business-critical processes, which will seriously impact service/application delivery and impair user experience. Therefore, it is imperative that you should closely observe if the memory shortage occurs due to data growth of the Modified and Standby memory lists and proactively initiate remedial actions before it causes severe memory contention on the target host. This can be achieved with the help of the OSMemoryTest.
This test periodically monitors the memory usage of the target Windows host, checks whether adequate physical memory is available to the host, and if not, promptly alerts users to the same. In the process, the test also reveals the amount of memory space is abnormally hogged by Modified or Standby memory list. This way, potential memory contention caused due to excessive memory usiliation by the Modified and Standby memory lists is brought to administrator's attention. Besides warning you of memory contention that Modified/Standby memory lists can cause, the test also empowers you to avoid probable memory shortage by initiating automated actions. These automated actions can be closely tracked using detailed diagnostics.
The default parameters associated with this test are:
USEGLANCE flag applies only to HP-UX systems. HP GlancePlus/UX is Hewlett-Packards's online performance monitoring and diagnostic utility for HP-UX based computers. There are two user interfaces of GlancePlus/UX -- Glance is character-based, and gpm is motif-based. Each contains graphical and tabular displays that depict how primary system resources are being utilized. In environments where Glance is run, the eG agent can be configured to integrate with Glance to pull out detailed metrics pertaining to the memory usage of the HP-UX systems that are being monitored. By default, this integration is disabled. This is why the USEGLANCE flag is set to No by default. You can enable the integration by setting the flag to Yes. If this is done, then the test polls the Glance interface of HP GlancePlus/UX utility to report the detailed diagnosis information pertaining to memory usage.
DYNAMIC MEMORY ENABLED flag applies only to the host system that is provisioned from a Microsoft Hyper-V Hypervisor. By default, DYNAMIC MEMORY ENABLED flag is set to No. If this flag is set to Yes, then, the eG agent will be able to pull out additional metrics pertaining to the memory usage of the host system provided, Dynamic Memory feature is enabled on the Microsoft HyperV Hypervisor through which the host system was provisioned.
By default, the detailed diagnosis of the Used physical memory measure of this test reports the number of instances of each process running on the VM, and the aggregated memory usage (in MB and %) of every process across all its instances. For example, if users to a VM are together having 15 instances of Chrome open on the machine at around the same time, then the detailed diagnosis of the Used physical memory measure will compute and display the collective memory usage of all 15 instances against the Application Name, Chrome. From this, you can quickly identify the exact process that is ‘collectively’ (i.e., across its instances) over-utilizing the memory. Sometimes, administrators might want to isolate not just the process, but also similar process arguments that are guilty of abnormal memory consumption. This granular insight will take administrators closer to the root-cause of the memory bottleneck on a desktop. For instance, in the Chrome example above, say 8 of the 15 instances are used to access the same YouTube video, and 7 instances are accessing a shopping site. In such a case, if memory usage is aggregated at the URL-level and not the process-level, then administrators can quickly identify which precise URL is draining memory - the YouTube video? or the shopping site? For this, detailed diagnostics should be grouped by process arguments (eg., URLs) and not just by process/application names. To enable grouping by arguments, set the GROUP PROCESSES WITH ARGUMENTS flag to Yes. By default, this flag is set to No.
A memory shortage caused due to memory space hogged by modified and standby memory lists has become an increasingly frequent and critical problem. The memory shortage can make a server stutter or run more slowly than usual. Such operational interruptions can make you spend more time on waiting for pages and programs to load, disturbing your work flow and leading to work delays. Moreover, memory shortage can not only impair user productivity, but can also bring crucial business processes to a halt, and can severely degrade overall user experience with the server. To avoid such an outcome, administrators need to rapidly empty the memory space unnecessarily hogged by the modified and standby memory lists. This way, administrators can ensure that adequate memory is always available for executing business-critical processes.
To enable administrators to achieve this, eG Enterprise offers ‘Automation Actions’. These actions are governed by the ‘Automation Action Enabled’ flag.
AUTOMATED ACTION ENABLED flag, if enabled, automatically initiates user-configured actions, so that the memory hogged by modified and standby memory lists can be cleared when memory utilization crosses a configured limit.
Note:
The ‘Automation Action Enabled’ parameters, once configured, will apply only to the chosen component. These settings will not be applied to other components even if the Apply to other components button is clicked in the Specific Test Configuration page.
AUTOMATION MEMORY LIMIT flag appears only if the Automated Action Enabled flag is enabled.
In AUTOMATION MEMORY LIMIT text box, specify the upper limit for memory utilization in percentage beyond which this test should trigger user-configured automation actions. By default, 95 percentage is set against this parameter. When the memory utilization reaches/exceeds the value specified in this text box, the user-configured actions will be automatically triggered. However, you can override this settings if required.
EMPTY MODIFIED MEMORY flag appears only if the Automated Action Enabled flag is enabled.
Modified memory contains cached data and code that is not actively in use by processes, the system and the system cache. This memory needs to be written out before it will be available for allocation to a process or for system use. You can easily clear this memory using the EMPTY MODIFIED MEMORY flag.
By default, EMPTY MODIFIED MEMORY flag is set to No. When this flag is set Yes, amount of memory assigned to the modified list will be automatically cleared if the memory utilization reaches/exceeds the value specified against the Automation Memory Limit parameter.
EMPTY STANDBY MEMORY flag appears only if the Automated Action Enabled flag is enabled.
Standby memory is a page of physical memory that is not actively used. When writing a series of frequently used information in the memory area, the programs and services running on the server will use part of memory as cache. The cache should be released and made available after executing programs and services. If the standby memory is not cleared on a regular basis, it can slow down the server operations. Therefore, it is necessary to clear the standby memory at regular intervals. This can easily done using the EMPTY STANDBY MEMORY flag.
By default, EMPTY STANDBY MEMORY flag is set to No. When this flag is set Yes, memory that is allocated to the standby page list will be automatically cleared if the memory utilization reaches/exceeds the value specified against the Automation Memory Limit parameter.
To make diagnosis more efficient and accurate, eG embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test, by default, for a particular server, choose the On option against DETAILED DIAGNOSIS. To disable the capability, click on the Off option.
The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:
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.
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