FSLogix Virtualization Driver FileId Cache – OS Test

When a user’s virtual desktop opens a file, the virtualization driver manages the file access and assigns a unique file ID to that file in the operating system or file system. The FileID cache stores these IDs along with metadata about the file (such as its location, permissions, etc.) so that future accesses to the same file can skip the step of querying the storage system to retrieve the file’s information again. This means that, even if the user opens the same file multiple times, the cache allows the system to quickly resolve the file reference and access it without additional overhead. Without a file ID cache, each access to a file might require looking up its file handle on the back-end file server, creating additional load on both the file system and the network. The cache reduces this load by storing the file handles locally in memory.

This test monitors the virtualization driver FileId cache, and reports the number of entries added/deleted/replaced. In addition, this test helps the administrator analyze if there is a need for extra memory resources.

Target of the test : A virtual desktop on the cloud

Agent deploying the test : A Remote agent

Outputs of the test : One set of results for the target virtual server to be monitored.

Configurable parameters for the test

Parameter	Description
Test Period	How often should the test be executed.
Host	The host for which the test is to be configured.
Port	The default port is NULL.
Inside View Using	To obtain the 'inside view' of performance of the cloud-hosted virtual desktops - i.e., to measure the internal performance of the virtual desktops - this test uses a light-weight eG VM Agent software deployed on each of the desktops. Accordingly, this parameter is by default set to eG VM Agent.
Report By User	This flag is set to Yes by default. The value of this flag cannot be changed. This implies that the virtual machines in VDI environments will always be identified using the login name of the user. In other words, in VDI environments, this test will, by default, report measures for every username_on_virtualmachinename.
Report Powered OS	This flag is relevant only for those tests that are mapped to the Inside View of Desktops layer. If this flag is set to Yes (which is the default setting), then the 'inside view' tests will report measures for even those virtual desktops that do not have any users logged in currently. Such desktops will be identified by their name and not by the username_on_virtualdesktopname. On the other hand, if this flag is set to No, then this test will not report measures for those virtual desktops to which no users are logged in currently.
Is Cloud VMs	Since this test runs for every virtual desktops component which is a cloud-hosted desktop group, this flag is set to Yes by default.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Added entries	Indicates the number of new entries added to the Virtualization Driver FileID cache.	Number
Current entries	Indicates the number of entries currently available in the Virtualization Driver FileID cache.	Number
Current memory usage	Indicates the amount of memory currently used by the Virtualization Driver FileID cache.	MB	A low value is desired for this measure. While sporadic spikes in memory usage could be caused by one/more rogue processes on the Virtualization Driver FileID cache, a consistent increase in this value could be a cause for some serious concern, as it indicates a gradual, but steady erosion of valuable memory resources.
Deleted entries	Indicates the number of entries deleted from the Virtualization Driver FileID cache.	Number
Entry access interval	Indicates the time interval it takes for the Virtualization Driver FileID cache between adding two different entries.	Seconds	A low value of this measure is desired.
Maximum access interval	Indicates the maximum time interval it takes for the Virtualization Driver FileID cache between adding two different entries.	Seconds
Replaced entries	Indicates the number of entries that were replaced in the Virtualization Driver FileID cache.	Number