Citrix MCS Storage Driver - OS Test
Machine Creation Services (MCS) Storage Optimization (MCSIO), is a new feature within MCS provisioning. MCSIO reduces I/O load through a two-tier caching system. An in-memory cache, known as the “temporary memory cache,” is used as the first storage tier. If the in-memory cache fills up, subsequent writes will be cached using an additional disk attached to the provisioned machine as the second tier - this is known as the “temporary disk cache.” To achieve this, MCSIO provisioned machines have an additional MCSIO driver to intercept and manage IO operations.
For improved I/O performance, both the storage tiers should be adequately sized, so that the likelihood of writes directly reaching the system disk reduces considerably. If the caches are not sized right, then they may soon run out of space for writes, causing the driver to direct writes to the system disk. This in turn will reduce cache hits, increase direct disk accesses, and thus, significantly degrade I/O performance. To avoid this, administrators should continuously monitor the I/O load on the MCSIO driver, understand how the driver uses the in-memory and disk cache for managing these I/O operations, and make sure that the caches are sized right to support these operations. This is where the Citrix MCS Storage Driver - OS test helps!
This test auto-discovers the virtual machines on the target virtual server and, for each virtual machine, tracks the I/O requests to the driver and reports the rate at which the driver reads from or writes into each of the caches and the system disks in order to process these requests. This way, the test reveals whether/not the caches are doing a good job of preventing direct disk accesses. Additionally, the test also closely monitors how the memory in the in-memory cache and the disk space in the cached disk is utilized, and proactively alerts administrators to any potential resource crunch in the caches. This way, the test provides useful sizing pointers to administrators.
This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick the desired Component type, set Performance as the Test type, choose the test from the disabled tests list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.
Target of the test : A Nutanix AHV VDI server
Agent deploying the test : A remote agent
Outputs of the test : One set of results for each virtual desktop on the Nutanix AHV VDI server being monitored.
| Parameter | Description |
|---|---|
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Test Period |
How often should the test be executed |
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Host |
The host for which the test is to be configured. |
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Port |
The port at which the specified host listens. By default, this is NULL |
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Prism Element IP |
If the eG manager had discovered the target Nutanix AHV server by connecting to the Nutanix Prism Element, then the IP address of the Nutanix Prism Element server used for discovering this Nutanix AHV server would be automatically displayed against the Prism Element IP parameter; similarly, the Prism Element User and Prism Element Password text boxes will be automatically populated with the Prism Element user credentials, using which Nutanix AHV discovery was performed. If this Nutanix AHV server has not been discovered using the Nutanix Prism Element, but you still want to monitor the Nutanix AHV server via the Prism Element, then select the IP address of the Prism Element server that you wish to use for monitoring the Nutanix AHV server from the Prism Element IP list. By default, this list is populated with the IP address of all Nutanix Prism Element hosts that were added to the eG Enterprise system at the time of discovery. Upon selection, the Prism Element user and Prism Element Password that were pre-configured for that Nutanix Prism Element will be automatically displayed against the respective text boxes. On the other hand, if the IP address of the Prism Element server of interest to you is not available in the list, then, you can add the details of the Prism Element server on-the-fly, by selecting the Other option from the Prism Element IP list. This will invoke the MANAGER DISCOVERY - VIRTUAL PLATFORM SETTINGS page. Refer to the Configuring eG Enterprise to Monitor Nutanix AHV |
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Prism Element User, Prism Element Password and Confirm Password |
If the eG manager had discovered the target Nutanix AHV server by connecting to the Nutanix Prism Element, then the IP address of the Nutanix Prism Element server used for discovering this Nutanix AHV server would be automatically displayed against thePrism Element IP parameter; similarly, the Prism Element User and Prism Element Password text boxes will be automatically populated with the Prism Element user credentials, using which Nutanix AHV discovery was performed. If this Nutanix AHV server has not been discovered using the Nutanix Prism Element, but you still want to monitor the Nutanix AHV server via the Prism Element, then select the IP address of the Prism Element server that you wish to use for monitoring the Nutanix AHV server from the Prism Element IP list. By default, this list is populated with the IP address of all Nutanix Prism Element hosts that were added to the eG Enterprise system at the time of discovery. Upon selection, the Prism Element User and Prism Element Password that were pre-configured for that Prism Element server will be automatically displayed against the respective text boxes. On the other hand, if the IP address of the Prism Element server of interest to you is not available in the list, then, you can add the details of the Prism Element server on-the-fly, by selecting the Other option from the Prism Element IP list. This will invoke the MANAGER DISCOVERY - VIRTUAL PLATFORM SETTINGS page. Refer to the Configuring eG Enterprise to Monitor Nutanix AHV |
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SSL |
By default, the Nutanix Prism Element server is SSL-enabled. Accordingly, the SSL flag is set to Yes by default. This indicates that the eG agent will communicate with the Prism Element server via HTTPS by default. |
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WebPort |
By default, the Nutanix Prism Element server listens on port 9440. This implies that while monitoring a Nutanix AHV server via the Prism Element server, the eG agent connects to port 9440. |
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Exclude VMs |
Administrators of some virtualized environments may not want to monitor some of their less-critical VMs - for instance, VM templates - both from 'outside' and from 'inside'. The eG agent in this case can be configured to completely exclude such VMs from its monitoring purview. To achieve this, provide a comma-separated list of VMs to be excluded from monitoring in the Exclude VMs text box. Instead of VMs, VM name patterns can also be provided here in a comma-separated list. For example, your Exclude VMs specification can be: *xp,*lin*,win*,vista. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside and outside views of all VMs on a virtual host by default. By providing a comma-separated list of VMs/VM name patterns in the Exclude VMs text box, you can make sure the eG agent stops collecting 'inside' and 'outside' view metrics for a configured set of VMs. |
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Ignore VMs Inside View |
Administrators of some high security Hyper-V environments might not have permissions to internally monitor one/more VMs. The eG agent can be configured to not obtain the 'inside view' of such ‘inaccessible’ VMs using the Ignore VMs Inside View parameter. Against this parameter, you can provide a comma-separated list of VM names, or VM name patterns, for which the inside view need not be obtained. For instance, your Ignore VMs Inside View specification can be: *xp,*lin*,win*,vista. Here, the * (asterisk) is used to denote leading and trailing spaces (as the case may be). By default, this parameter is set to none indicating that the eG agent obtains the inside view of all VMs on a Hyper-V host by default. Note: While performing VM discovery, the eG agent will not discover the operating system of the VMs configured in the Ignore VMs Inside View text box. |
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Ignore WINNT |
By default, the eG agent does not support the inside view for VMs executing on Windows NT operating systems. Accordingly, the Ignore WINNT flag is set to Yes by default. |
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Inside View Using |
By default, this test obtains the “inside view” of VMs using the eG VM Agent. Accordingly, the Inside view using flag is set to eG VM Agent by default. The eG VM Agent is a piece of software, which should be installed on every VM on a hypervisor. Every time the eG agent runs this test, it uses the eG VM Agent to pull relevant 'inside view' metrics from each VM. Once the metrics are collected, the eG agent then communicates with each VM agent and pulls these metrics, without requiring administrator privileges. Refer to Configuring the Remote Agent to Obtain the Inside View of VMs for more details on the eG VM Agent. |
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Domain, Admin User, and Admin Password, and Confirm Password |
By default, these parameters are set to none. This is because, by default, the eG agent collects 'inside view' metrics using the eG VM agent on each VM. Domain administrator privileges need not be granted to the eG agent if it uses this default approach to obtain the 'inside view' of Windows VMs. |
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Report By User |
While monitoring a Nutanix AHV server, the Report By Userflag is set to No by default, indicating that by default, the guest operating systems on the AHV server are identified using the hostname specified in the operating system. On the other hand, while monitoring AHV desktop environments, this flag is set to Yes by default; this implies that in case of VDI servers, by default, the guests will be identified using the login of the user who is accessing the guest OS. In other words, in VDI environments, this test will, by default, report measures for every username_on_virtualmachinename. |
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Report Powered OS |
This flag becomes relevant only if thereport by user flagis set to ‘Yes’. If the Report Powered OS flag is set to Yes (which is the default setting), then this test will report measures for even those VMs that do not have any users logged in currently. Such guests will be identified by their virtualmachine name and not by the username_on_virtualmachinename. On the other hand, if the Report Powered OS flag is set to No, then this test will not report measures for those VMs to which no users are logged in currently. |
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DD Frequency |
Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency. |
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Detailed Diagnosis |
To make diagnosis more efficient and accurate, the eG Enterprise 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 for a particular server, choose the On option. 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:
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| Measurement | Description | Measurement Unit | Interpretation |
|---|---|---|---|
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Cache memory data reads |
Indicates the rate at which data is read from the in-memory cache. |
KB/Sec |
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Cache memory data writes |
Indicates the rate at which data is written to the in-memory cache. |
KB/Sec |
A steady drop in the value of this measure could indicate a writing bottleneck. One of the reasons for this could be the lack of enough memory. Check the value of the Cache memory utilization measure to determine whether/not there is a memory crunch. |
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Cache memory data reads and writes |
Indicates the rate at which data is written to and read from the in-memory cache. |
KB/Sec |
A steady drop in the value of this measure is indicative of an I/O bottleneck. |
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Cache memory reads |
Indicates the rate at which read operations are performed on the in-memory cache. |
Reads/Sec |
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Cache memory writes |
Indicates the rate at which write operations are performed on the in-memory cache. |
Writes/Sec |
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Cache memory IOPS |
Indicates the rate at which read and write operations are performed on the in-memory cache. |
Operations/Sec |
|
|
Cache memory target size |
Indicates the amount of memory that the MCS storage driver will aim to use. |
MB |
|
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Cache memory used |
Indicates the amount of memory that the driver has actually used. |
MB |
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Cache memory free |
Indicates the amount of memory that is unused. |
MB |
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Cache memory utilization |
Indicates the percentage of memory that the driver has utilized. |
Percent |
A value close to 100% is a cause for concern as it indicates that the in-memory cache is rapidly running out of memory. You may want to allocate more RAM to the cache to make sure that the writes do not spill over to the cache disk. |
|
Cache disk data reads |
Indicates the rate at which data is read from the cache disk. |
KB/Sec |
|
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Cache disk data writes |
Indicates the rate at which data is written to the cache disk. |
KB/Sec |
A steady drop in the value of this measure could indicate a writing bottleneck. One of the reasons for this could be the lack of enough disk space in the cache disk. Check the value of the Cache disk utilization measure to determine whether/not there is a space crunch. |
|
Cache disk data reads and writes |
Indicates the rate at which data is written to and read from the cache disk. |
KB/Sec |
A steady drop in the value of this measure is indicative of an I/O bottleneck. |
|
Cache disk reads |
Indicates the rate at which read operations are performed on the cache disk. |
Reads/Sec |
|
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Cache disk writes |
Indicates the rate at which write operations are performed on the cache disk. |
Writes/Sec |
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Cache disk IOPS |
Indicates the rate at which read and write operations are performed on the cache disk. |
Operations/Sec |
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Cache disk size |
Indicates the current size of the cache disk. |
MB |
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Cache disk used |
Indicates the amount of space that the driver has used in the cache disk. |
MB |
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Cache disk free |
Indicates the amount of space that is unused in the cache disk. |
MB |
|
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Cache disk utilization |
Indicates the percentage of space used in the cache disk. |
Percent |
A value close to 100% is a cause for concern as it indicates that the cache disk is running out of disk space. You may want to expand the capacity of the cache disk to make sure that the writes do not spill over to the system disks. |
|
Storage driver read requests |
Indicates the number of read requests that were received by the MCS storage driver since boot. |
Number |
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Storage driver write requests |
Indicates the number of write requests that were received by the MCS storage driver since boot. |
Number |
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Storage driver read and write requests |
Indicates the number of read and write requests that were received by the MCS storage driver since boot. |
Number |
This is a good indicator of the I/O load on the driver. |
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System disk data reads |
Indicates the rate at which data is read from the system disks. |
KB/Sec |
|
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System disk data writes |
Indicates the rate at which data is written to the system disks. |
KB/Sec |
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System disk data reads and writes |
Indicates the rate at which data is written to and read from the system disks. |
KB/Sec |
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System disk reads |
Indicates the rate at which reads are performed from the system disks. |
Reads/Sec |
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System disk writes |
Indicates the rate at which writes are performed into the system disks. |
Writes/Sec |
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System disk IOPS |
Indicates the rate at which I/O operations are performed on system disks. |
Operations/Sec |
A zero value is desired for this measure. |
