Azure Sentinel Cost Management and Optimization Strategies

Azure Sentinel is a cloud-native security information and event management (SIEM) solution that can help you detect and respond to threats in real-time. It's a powerful tool, but it can also be a significant cost.

To get the most out of Azure Sentinel, it's essential to implement cost management and optimization strategies. This means understanding how Azure Sentinel pricing works and making informed decisions about your usage.

Here are some key facts to keep in mind: Azure Sentinel pricing is based on the number of data sources and the amount of data ingested. Each data source is billed separately, and the cost varies depending on the type of data source.

To minimize costs, consider implementing a data retention policy that limits the amount of data stored in Azure Sentinel. This can help reduce storage costs and improve performance.

Microsoft Sentinel's cost structure is based on data ingestion, retention, and usage. You're billed per GB of data ingested into Sentinel, with several pricing tiers available, each with its respective discounts.

The biggest impact on total costs will come down to data ingestion, which is billed per GB per month. Data retention is also a factor, with three months of free retention and additional months billed accordingly.

To view costs, use cost analysis in the Azure portal, which shows costs in graphs and tables for different time intervals. You can also view costs against budgets and forecasted costs, helping you identify spending trends and potential overspending.

Cost analysis provides detailed views of your Azure usage and costs, with options to apply various controls and filters. For example, you can view daily costs for a specific time frame by selecting the Accumulated costs or Daily costs option.

To view only the costs associated with Microsoft Sentinel, select Add filter, Service name, and then select the service names Sentinel, Log Analytics, and Azure Monitor.

Here are the pricing tiers for Pay-As-You-Go:

You can also use Azure Prepayment to pay for Microsoft Sentinel charges, but it can't be used to pay bills to non-Microsoft organizations or for products from the Azure Marketplace.

Cost management is a crucial aspect of using Azure Sentinel, and understanding how to manage costs can help you optimize your budget. The biggest impact on total costs will come down to how much data you're planning to ingest into Sentinel, with billing based on data ingestion per GB/month.

To reduce costs, consider moving to a Log Analytics dedicated cluster if you ingest at least 100 GB into your Microsoft Sentinel workspace or workspaces in the same region. This can decrease costs by aggregating data volume across workspaces.

You can also reduce data retention costs by adjusting the data retention period in Log Analytics. By default, Microsoft Sentinel retains data for the first 90 days, but you can adjust this period to reduce costs. For example, you can enroll tables that contain secondary security data in the Auxiliary logs plan (now in Preview) to store high-volume, low-value logs at a low price.

To view costs, use cost analysis in the Azure portal, which shows detailed views of your Azure usage and costs. You can apply various controls and filters to see charts of your daily costs for a certain time frame or view only the costs associated with Microsoft Sentinel.

Here are some key cost management options to consider:

Creating budgets is a crucial step in managing costs, and it's easy to do in Azure. You can create budgets to manage costs and create alerts that automatically notify stakeholders of spending anomalies and overspending risks.

Budgets are created for Azure subscriptions and resource groups, making them useful as part of an overall cost monitoring strategy. You can create budgets with filters for specific resources or services in Azure if you want more granularity in your monitoring.

Filters help ensure that you don't accidentally create new resources that cost you more money. You can use filters to view only the costs associated with Microsoft Sentinel, for example, by selecting Service name and then selecting the service names Sentinel, Log Analytics, and Azure Monitor.

Budgets and alerts are based on spending compared to budget and cost thresholds. Alerts will notify stakeholders when spending exceeds these thresholds, helping you stay on top of your costs.

To create a budget, you can use the Microsoft Cost Management + Billing hub. From there, select Cost Management in the left navigation and then select the scope or set of resources to investigate, such as an Azure subscription or resource group.

Here are the steps to create a budget:

By creating budgets and setting up alerts, you can proactively manage your costs and avoid overspending.

Defining a volume cap in Log Analytics can help you manage unexpected increases in data volume and stay within your budget.

You can enable a daily volume cap in Log Analytics to limit the daily ingestion for your workspace. This is especially useful for managing unexpected spikes in data volume.

To define a daily volume cap, select Usage and estimated costs in the left navigation of your Log Analytics workspace, and then select Daily cap.

The daily cap can help you limit unplanned charges and stay within your budget.

Here are the steps to define a daily volume cap:

By defining a daily volume cap, you can ensure that your data volume stays within your budget and avoid unexpected charges.

Separate non-security data in a different workspace to avoid incurring Microsoft Sentinel costs. Microsoft Sentinel analyzes all data ingested into Microsoft Sentinel-enabled Log Analytics workspaces, so it's best to keep non-security operations data separate.

You can access operational data stored in standalone Azure Log Analytics workspaces by using cross-workspace querying in the log exploration experience and workbooks. This allows you to hunt or investigate threats without being charged for non-security data.

Microsoft Sentinel can't be used for cross-workspace analytics rules and hunting queries unless it's enabled on all the workspaces that contain the data you want to analyze.

Data can be retained in Microsoft Sentinel for up to 12 years beyond the initial free retention periods. You can retain data for compliance purposes and access it for incident investigation.

There are different retention periods depending on how data is ingested into the workspace. For Analytics Logs, data is retained for 90 days for free, and then charged at the standard Azure Monitor retention prices up to 2 years. For Basic Logs and Auxiliary Logs, data is retained for 30 days for free.

Data in long-term retention can be searched using asynchronous search jobs, which incur a cost for the data scanned. You can also restore data to enable full interactive analytics query capabilities.

Here's a summary of the free retention periods:

Once the free retention periods end, you'll be charged for data retention based on the standard Azure Monitor retention prices.

Log Restore can be a game-changer for historical log data. It brings historical log data into the current hot cache for high performing queries and analytics.

To use Log Restore, you simply specify a target table and a specific time range for the data you wish to restore. This process takes only a few minutes, and the target log data is available within the workspace with full KQL support for high performance queries.

Log Data Restore is ideally adapted for restoring historical logs stored in Log Data Archive. This feature is a great way to access and analyze historical data without having to worry about storage space or performance issues.

The pricing for Log Data Restore is based on the amount of data ingested into Microsoft Sentinel, with a minimum charge of 2 TB for 12 hours. This charge is pro-rated hourly, so you only pay for what you use.

Optimizing your Azure Sentinel costs requires some careful planning, but it's worth the effort. You can start by moving to a Log Analytics dedicated cluster if you ingest at least 100 GB into your Microsoft Sentinel workspace or workspaces in the same region.

This can help decrease costs by aggregating data volume across workspaces and sharing the Log Analytics Commitment Tier set on the cluster. You can also reduce data retention costs by adjusting the data retention period in Log Analytics, which retains data by default in interactive form for the first 90 days.

To further reduce costs, you can enroll tables that contain secondary security data in the Auxiliary logs plan, which allows you to store high-volume, low-value logs at a low price.

Here are some key considerations for moving to a dedicated cluster for cost optimization:

Get-AzPriceRecommendation.Ps1 is a valuable tool for determining the optimal pricing tier for your Microsoft Sentinel workspaces. It's a PowerShell script that helps you identify areas where you can save money.

The script works by looping through all your subscriptions and finding all workspaces deployed. It then performs a KQL query against each workspace to determine the average daily data ingest based on the last month.

These results are compared with a fixed table of thresholds to determine the optimal pricing tier. The thresholds for these pricing tiers are currently set based on "list" prices as of February 2nd, 2022, in the West Europe region.

You can use the Excel sheet mentioned in the script to determine thresholds that suit your environment best. This will give you a more accurate picture of your costs and help you make informed decisions.

Here are the steps the script takes to determine the optimal pricing tier:

All results are gathered in an overview and automatically exported as a CSV at the end.

To optimize log costs, consider moving to a Log Analytics dedicated cluster if you ingest at least 100 GB into your Microsoft Sentinel workspace or workspaces in the same region.

A dedicated cluster can decrease costs by aggregating data volume across workspaces and allowing for cost savings and efficiencies. You can add multiple Microsoft Sentinel workspaces to a Log Analytics dedicated cluster.

The maximum number of clusters per region and subscription is two, and all workspaces linked to a cluster must be in the same region. The maximum of workspaces linked to a cluster is 1000.

To view costs, use cost analysis in the Azure portal, which shows detailed views of your Azure usage and costs. You can apply various controls and filters to see charts of your daily costs for a certain time frame.

To reduce data retention costs, adjust the data retention period in Log Analytics, which retains data by default in interactive form for the first 90 days. You can also reduce costs by enrolling tables that contain secondary security data in the Auxiliary logs plan (now in Preview).

The Auxiliary logs plan allows you to store high-volume, low-value logs at a low price, with a lower-cost 30-day interactive retention period at the beginning to allow for summarization and basic querying. You can also enroll these tables in the Basic logs plan, which offers similar functionality to auxiliary logs but with less of a cost savings.

Here are some key points to consider when optimizing log costs:

* OptionDescriptionDedicated ClusterAggregates data volume across workspaces, decreasing costs and improving efficiencyAuxiliary Logs PlanStores high-volume, low-value logs at a low price, with a lower-cost 30-day interactive retention periodBasic Logs PlanOffers similar functionality to auxiliary logs, but with less of a cost savings

To get the most out of these options, use the Get-AzSentinelPriceRecommendation.ps1 script to determine the average daily ingest rate for your workspaces and compare it with fixed thresholds to determine the optimal pricing tier.

The thresholds for these pricing tiers are currently determined based on list prices as of February 2nd 2022 based on the West Europe region. You should use the Excel sheet mentioned earlier to determine thresholds that suit your environment best.

To define a daily volume cap in Log Analytics, select Usage and estimated costs in the left navigation of your Log Analytics workspace, and then select Daily cap. This can help you manage unexpected increases in data volume and stay within your limit.

By implementing these strategies, you can optimize your log costs and reduce unnecessary expenses.