---
id: 409d4193-e70e-43bb-a88d-433799362b1e
---

# MongoDB virtual memory usage incident.
---

This incident type refers to an issue with high virtual memory usage in a MongoDB instance. It can lead to performance degradation or even service downtime. It requires immediate attention from the responsible team to investigate the root cause and take corrective measures to resolve the issue.

### Parameters
```shell
# Environment Variables

export HOSTNAME="PLACEHOLDER"

export PORT="PLACEHOLDER"

export DATABASE_NAME="PLACEHOLDER"

export SWAP_SIZE="PLACEHOLDER"

export SWAP_FILE_PATH="PLACEHOLDER"

export COLLECTION_NAME="PLACEHOLDER"
```

## Debug

### Connect to the MongoDB instance
```shell
mongo ${HOSTNAME}:${PORT}
```

### List the databases
```shell
show dbs
```

### Select a database
```shell
use ${DATABASE_NAME}
```

### Check the size of all collections in the database
```shell
db.getCollectionNames().forEach(function(collname) { print(db.getCollection(collname).count() + "\t" + collname) })
```

### Check the virtual memory usage of the MongoDB instance
```shell
db.serverStatus().mem.virtual
```

### Check the available memory on the server
```shell
free -m
```

### Check the system logs for any memory-related errors
```shell
grep -i "out of memory" /var/log/syslog
```

### Check the MongoDB logs for any errors
```shell
tail -f /var/log/mongodb/mongod.log
```

### Check the resource usage of the MongoDB process
```shell
top -p $(pgrep mongod) -c
```

### Check the configuration file for any memory-related settings
```shell
cat /etc/mongod.conf | grep -i "memory"
```

## Repair

### Increase the swap space to allow MongoDB to use more virtual memory.
```shell


#!/bin/bash



# Get the current swap usage

SWAP=$(free | awk '/^Swap:/ {print $3}')



# Check if swap is already being used

if [ $SWAP -eq 0 ]; then

    # Increase the swap space by adding a new swap file

    sudo fallocate -l ${SWAP_SIZE} ${SWAP_FILE_PATH}

    sudo chmod 600 ${SWAP_FILE_PATH}

    sudo mkswap ${SWAP_FILE_PATH}

    sudo swapon ${SWAP_FILE_PATH}



    # Update the /etc/fstab file to enable the swap file at boot time

    echo "${SWAP_FILE_PATH} none swap sw 0 0" | sudo tee -a /etc/fstab



    # Verify the new swap space

    free

else

    echo "Swap space is already being used."

fi


```

### Optimize the MongoDB queries to reduce the memory usage.
```shell


#!/bin/bash



# Define the MongoDB database name and collection to optimize

DB_NAME=${DATABASE_NAME}

COLLECTION_NAME=${COLLECTION_NAME}



# Connect to the MongoDB instance and run the optimization command

mongo $DB_NAME --eval "db.$COLLECTION_NAME.reIndex()"



# Output a success message

echo "MongoDB query optimization and memory usage reduction complete."


```

### Remove unused indexes or collections to free up memory space.
```shell


#!/bin/bash



# Define the MongoDB database and collection to remove

database_name=${DATABASE_NAME}

collection_name=${COLLECTION_NAME}



# Connect to the MongoDB instance and remove the collection

mongo $database_name --eval "db.$collection_name.drop()"



# Print a message to confirm the collection was removed

echo "The $collection_name collection has been removed from the $database_name database."


```

This incident type refers to an issue with high virtual memory usage in a MongoDB instance. It can lead to performance degradation or even service downtime. It requires immediate attention from the responsible team to investigate the root cause and take corrective measures to resolve the issue.


This incident type indicates that there is a high latency issue in the execution of a Spark job. Spark is a distributed computing framework that is used for processing large datasets. High latency in this context means that the time taken to execute the Spark job is significantly longer than expected or normal. This can result in delays in processing data and can impact the performance of the application or system that is utilizing Spark.


High Latency Incident for Spark Job Execution.

This incident type relates to Redis, a popular in-memory data structure store that is widely used in software development. The incident occurs when there is high memory consumption in Redis, which can lead to performance issues and potentially cause the system to crash. This incident type is critical as it can impact the functionality of the system and requires immediate attention to resolve.


High memory consumption in Redis

A Rabbitmq memory high incident occurs when a node uses more than 90% of the allocated RAM. This can cause performance issues and impact the overall functionality of the system. It is important to promptly address this issue to prevent any further damage.


Rabbitmq memory high incident.

This incident type involves an alert triggered when read latency is higher than usual for a MongoDB host. The alert is triggered when at least 100% of the average read latency values have been more than 2 deviations above the predicted values during the last 15 minutes. The incident requires monitoring and investigation to identify the root cause of the increased read latency and take appropriate actions to resolve it.


Read latency higher than average for MongoDB host.

This incident type refers to a situation where the write latency for a MongoDB database is higher than the average. This might cause delays in write operations and can negatively impact the performance of the system. The incident might be triggered by an alert that indicates that the write latency has exceeded a certain threshold, and it requires immediate attention from a software engineer to identify and resolve the underlying issue. The incident can be resolved by identifying and fixing the root cause of the latency issue, and ensuring that the system is functioning within acceptable performance parameters.


MongoDB Write Latency Higher Than Average

```shell
# Environment Variables

export HOSTNAME="PLACEHOLDER"

export PORT="PLACEHOLDER"

export DATABASE_NAME="PLACEHOLDER"

export SWAP_SIZE="PLACEHOLDER"

export SWAP_FILE_PATH="PLACEHOLDER"

export COLLECTION_NAME="PLACEHOLDER"
```


### Connect to the MongoDB instance

```shell
mongo ${HOSTNAME}:${PORT}
```

### List the databases

```shell
show dbs
```

### Select a database

```shell
use ${DATABASE_NAME}
```

### Check the size of all collections in the database

```shell
db.getCollectionNames().forEach(function(collname) { print(db.getCollection(collname).count() + "\t" + collname) })
```

### Check the virtual memory usage of the MongoDB instance

```shell
db.serverStatus().mem.virtual
```

### Check the available memory on the server

```shell
free -m
```

### Check the system logs for any memory-related errors

```shell
grep -i "out of memory" /var/log/syslog
```

### Check the MongoDB logs for any errors

```shell
tail -f /var/log/mongodb/mongod.log
```

### Check the resource usage of the MongoDB process

```shell
top -p $(pgrep mongod) -c
```

### Check the configuration file for any memory-related settings

```shell
cat /etc/mongod.conf | grep -i "memory"
```


### Increase the swap space to allow MongoDB to use more virtual memory.

```shell


#!/bin/bash



# Get the current swap usage

SWAP=$(free | awk '/^Swap:/ {print $3}')



# Check if swap is already being used

if [ $SWAP -eq 0 ]; then

    # Increase the swap space by adding a new swap file

    sudo fallocate -l ${SWAP_SIZE} ${SWAP_FILE_PATH}

    sudo chmod 600 ${SWAP_FILE_PATH}

    sudo mkswap ${SWAP_FILE_PATH}

    sudo swapon ${SWAP_FILE_PATH}



    # Update the /etc/fstab file to enable the swap file at boot time

    echo "${SWAP_FILE_PATH} none swap sw 0 0" | sudo tee -a /etc/fstab



    # Verify the new swap space

    free

else

    echo "Swap space is already being used."

fi


```

### Optimize the MongoDB queries to reduce the memory usage.

```shell


#!/bin/bash



# Define the MongoDB database name and collection to optimize

DB_NAME=${DATABASE_NAME}

COLLECTION_NAME=${COLLECTION_NAME}



# Connect to the MongoDB instance and run the optimization command

mongo $DB_NAME --eval "db.$COLLECTION_NAME.reIndex()"



# Output a success message

echo "MongoDB query optimization and memory usage reduction complete."


```

### Remove unused indexes or collections to free up memory space.

```shell


#!/bin/bash



# Define the MongoDB database and collection to remove

database_name=${DATABASE_NAME}

collection_name=${COLLECTION_NAME}



# Connect to the MongoDB instance and remove the collection

mongo $database_name --eval "db.$collection_name.drop()"



# Print a message to confirm the collection was removed

echo "The $collection_name collection has been removed from the $database_name database."


```


MongoDB virtual memory usage incident.

Overview

Parameters

Debug

Connect to the MongoDB instance

List the databases

Select a database

Check the size of all collections in the database

Check the virtual memory usage of the MongoDB instance

Check the available memory on the server

Check the MongoDB logs for any errors

Check the resource usage of the MongoDB process

Repair

Increase the swap space to allow MongoDB to use more virtual memory.

Optimize the MongoDB queries to reduce the memory usage.

Remove unused indexes or collections to free up memory space.

Learn more

Related Runbooks

High Latency Incident for Spark Job Execution.

High memory consumption in Redis

Rabbitmq memory high incident.

Read latency higher than average for MongoDB host.

Support