Mongo Memory Test

MongoDB maps data files to memory for managing and interacting with all data. Memory mapping assigns files to a block of virtual memory with a direct byte-for-byte correlation. MongoDB memory maps data files to memory as it accesses documents. Unaccessed data is not mapped to memory. This provides MongoDB with an extremely fast and simple method for accessing and manipulating data.

This implies that if MongoDB is not sized with adequate virtual memory, then data accesses are bound to slow down, thus adversely impacting user experience with the server. To avoid this, administrators should periodically run the Mongo Memory test. This test monitors how the target MongoDB server utilizes the virtual memory, proactively detects potential memory contentions, and promptly alerts administrators to it, so that they can initiate measures to avert the contention and the consequent slow down.

Target of the test : A MongoDB server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the Mongo database server being 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 port number at which the specified host listens
Database Name	The test connects to a specific Mongo database to run API commands and pull metrics of interest. Specify the name of this database here. The default value of this parameter is admin.
Username and Password	The eG agent has to be configured with the credentials of a user who has the required privileges to monitor the target MongoDB instance, if the MongoDB instance is access control enabled. To know how to create such a user, refer to How to monitor access control enabled MongoDB database? . If the target MongoDB instance is not access control enabled, then, specify none against the Username and Password parameters.
Confirm Password	Confirm the password by retyping it here.
Authentication Mechanism	Typically, the MongoDB supports multiple authentication mechanisms that users can use to verify their identity. In environments where multiple authentication mechanisms are used, this test enables the users to select the authentication mechanism of their interest using this list box. By default, this is set to None. However, you can modify this settings as per the requirement.
SSL	By default, the SSL flag is set to No, indicating that the target MongoDB server is not SSL-enabled by default. To enable the test to connect to an SSL-enabled MongoDB server, set the SSL flag to Yes.
CA File	A certificate authority (CA) file contains root and intermediate certificates that are electronically signed to affirm that a public key belongs to the owner named in the certificate. If you are looking to monitor the certificates contained within a CA file, then provide the full path to this file in the CA File text box. For example, the location of this file may be: C:\cert\rootCA.pem. If you do not want to monitor the certificates in a CA file, set this parameter to none.
Certificate Key File	A Certificate Key File specifies the path on the server where your private key is stored. If you are looking to monitor the Certificate Key File, then provide the full path to this file in the Certificate Key File text box. For example, the location of this file may be: C:\cert\mongodb.pem. If you do not want to monitor the certificates in a CA file, set this parameter to none.
CA PEM File	A .pem file is a container that may just include the public certificate or the entire certificate chain (private key, public key and root certificates). If the connection requires server authentication and the server certificate is in the .pem format, then, the target instance presents the CA PEM File that contains the server certificate to its clients to establish the instance's identity. Therefore, you should specify the full path to the CA PEM file available in the target MongoDB server in the CA PEM File text box. For example, the location of this file may be: C:\app\openSSL\SSLcert\test-ca.pem.
Client PEM File	If the target instance requires a certificate key file that is in .pem format from the client to verify the client's identity, then, to establish a connection with the target server, the eG agent should access the client certificate. For this, specify the full path to the Client PEM file in the Client PEM File text box. For example, the location of this file may be: C:\app\openSSL\SSLcert\test-client.pem.
CA Cert File	This parameter is applicable only if the target MongoDB server is SSL-enabled and CA PEM File parameter is set to none.The certificate file is a public-key certificate following the x.509 standard. It contains information about the identity of the server, such as its name, geolocation, and public key. Essentially, it’s a certificate that the server serves to the connecting users to prove that they are what they claim to be. Therefore, specify the full path to the server root certificate or certificate file that is signed by the CA in .crt file format for the server in the CA Cert File text box. For example, the location of this file may be: C:\app\eGurkha\JRE\lib\security\mongodb-test-ca.crt. By default, this parameter is set to none.
Client Cert File	This parameter is applicable only if the target MongoDB server is SSL-enabled and Client PEM File parameter is set to none.In order to collect metrics from the target MongoDB, the eG agent requires client certificate in .p12 format. Hence, specify the full path to the Client certificate file in .p12 format in the Client Cert File text box. For example, the location of this file may be: C:\app\eGurkha\JRE\lib\security\test-client.p12 . To know how to generate .p12 file from Client PEM file, refer to How to import a Certificate that is in the PEM Format? By default, this parameter is set to none.
Client Cert Password	Provide the password for .p12 Client certificate file in the Client Cert Password text box.
AWS Key ID, AWS Secret Key,Confirm Password	If you are monitoring MongoDB server hosted on the AWS cloud, the eG agent has to be configured with the AWS AccessKey ID and Secret Key to connect with the AWS cloud and collect the required metrics. Therefore, Specify the AWS Key ID and AWS Secret Key and confirm the password by re-typing it in the Confirm Password text box. To obtain the AWS Access key and secret key, refer toObtaining AWS Access Key and Obtaining AWS Secret Key.
Atlas URI	MongoDB Atlas is a NoSQL Database-as-a-Service offering in the public cloud. If the target MongoDB server is deployed and managed in MongoDB Atlas, then the eG agent has to be configured with the MongoDB Atlas connection URI,a unique identifier for connecting to a MongoDB server, in the Atlas URI text box to access the target MongoDB server hosted on Atlas and collect the required metrics.

Measurements made by the test
Measurement	Description	Measurement Unit	Interpretation
Total memory	If the MMAPv1 storage engine is in use, then this indicates the amount of virtual memory mapped by the database. Because MongoDB uses memory-mapped files, this value is likely to be roughly equivalent to the total size of your database or databases. This value does not include memory allocated to journal. If the WiredTiger storage engine is in use, then the value of this measure displays the quantity of virtual memory provided to the mongod process. This value includes memory allocated to the journal.	GB
Available memory	Indicates the amount of memory unused.	GB	Note that this measure will be reported only if the target server uses the MMAPv1 storage engine. The value of this measure is the difference between the value of the Total memory and Used memory measures.
Used memory	Indicates the amount of RAM currently used by the target server.	GB	During normal use, this value tends to grow. In dedicated database servers, this number tends to approach the total amount of system memory.
Memory usage	Indicates the percentage of memory used.	Percent	This value is computed using the following formula: (Used memory / Total memory) * 100 A value close to 100% indicates that almost all the memory is been utilized. No free memory or very little free memory will be available for database operations in this case, causing database performance to severely deteriorate. You may want to increase the memory allocation to the database instance to pre-empt this.
Allocated memory with journal	Indicates the amount of mapped memory, including the memory used for journaling.	GB	Note that this measure will be reported only if the target server uses the MMAPv1 storage engine and journaling is enabled. The value of this measure will always be twice the value of the Total memory measure.
Heap memory used	Indicates the amount of Java heap memory used by the MongoDB server being monitored.	GB	A low value is desired for this measure. Note that this measure will be reported only if the target MongoDB server runs on Unix/Linux.
Page faults	Indicates the number of page faults generated on the target server.	Number	Page faults refer to operations that require the database server to access data which isn’t available in active memory. The page faults counter may increase dramatically during moments of poor performance and may correlate with limited memory environments and larger data sets. Limited and sporadic page faults do not necessarily indicate an issue.
Free percentage	Indicates the percentage of free memory or memory available for use.	Percent