Configuring backup and replication

Prerequisite knowledge

Before you begin working on this section, you should be familiar with the concepts in the following articles from Splunk documentation:

• The basics of indexer cluster architecture
• Multisite indexer cluster architecture
• How clustered indexing works

Questions to answer before beginning backup

1. Business Continuity Objectives:
   • What are your recovery time objectives (RTO) and recovery point objectives (RPO) for your Splunk data?
2. Splunk Infrastructure:
   • How is your Splunk deployment structured? Are you utilizing clustered features, such as indexer clustering or search head clustering?
   • How many indexers are in your Splunk deployment, and what is their average data ingest rate?
   • Are you using Splunk Enterprise Security or Splunk ITSI?
3. Current Backup Mechanism:
   • Do you have an existing backup mechanism in place? If so, what are its capabilities and limitations?
   • How frequently do you currently perform backups of your critical systems?
4. Operational Constraints:
   • Are there specific time windows when backups must (or must not) occur due to operational needs or system loads?
   • Are there any bandwidth or resource constraints to be aware of when planning backup strategies?
5. Data Retention and Compliance:
   • Are there specific data retention requirements or policies that your organization adheres to?
   • Do you have any industry or regulatory compliance standards (for example, GDPR, HIPAA) that affect how data is backed up and retained?
6. Disaster Recovery Scenarios:
   • Have you identified specific disaster scenarios (for example, data corruption, server failure, data center outages) you want to protect against?
   • Have you ever had to restore Splunk data in the past? If so, what was that experience like?
7. Budget and Resource Allocation:
   • Do you have a dedicated budget for backup and disaster recovery solutions?
   • What internal or external resources (personnel, hardware, software) are available or allocated for backup and disaster recovery efforts?
8. Data Integrity and Validation:
   • How will you validate the integrity of backups? Do you need to perform regular test restores?
   • Do you have mechanisms or processes in place to monitor and alert on backup failures?
9. Geographic Considerations:
   • Is geographic redundancy necessary for your backup strategy (for example, backing up data to a different region or data center)?
10. Integration with Other Systems:
    • Are other systems or data sources interdependent with your Splunk data, which might need to be considered in a coordinated backup or restore strategy?

Built-in replication compared to additional backups

While the native replication mechanisms, which are the Replication Factor (RF) and Search Factor (SF), offer real-time data resilience, traditional backups provide a safety net against data corruption, failures, or other significant disruptions. As we get deeper into this section, we'll contrast the proactive, immediate recovery benefits of built-in replication in the Splunk platform against the more retrospective, long-term data retention advantages of backups. By the end, you'll have a clear understanding of when and why to apply each method, and how they collaboratively enhance the overall resiliency of your Splunk deployment.

In the context of safeguarding Splunk index data, the primary approach should revolve around utilizing the search factor and replication factor. These built-in mechanisms provide an intrinsic layer of data protection, ensuring that indexed data is appropriately duplicated across multiple peers in the Splunk cluster. By leveraging these factors, organizations can maintain data accessibility and resilience even in the face of potential node failures or data corruption scenarios. Before considering additional backup strategies, it's imperative to set and optimize these factors according to the specific needs and infrastructure of the deployment, as they serve as the foundational pillars of data reliability within the Splunk platform.

Reference the Splunk Validated Architectures for assistance in designing the Splunk deployment that will meet your organization's backup and recovery goals.

Challenges and considerations with traditional backup strategies for indexes

While traditional backups can provide a snapshot of your Splunk data at a particular point in time, there are inherent risks associated with this method. These include the following:

• The dynamic nature of Splunk data means that backups can quickly become outdated, potentially leading to data gaps in the event of a restore.
• Restoring the Splunk platform from a conventional backup can be time-consuming, potentially leading to prolonged service disruptions.
• The restoration process might not always guarantee the integrity of the indexed data, especially if the backup was taken during heavy indexing or searching operations.

As such, while traditional backups can serve as a supplementary layer of protection, they should not replace the native resiliency provided by the proper configuration of the search factor and replication factor in the Splunk platform. Before embarking on a traditional backup strategy, you should weigh the benefits for each index type against these potential challenges to make informed decisions.

• Hot Indexes:
  • Challenges: Hot indexes are the active indexes, where new data is continuously being written. They can be volatile and are often locked, making them more challenging to backup.
  • Considerations: Due to their active nature, it is typically recommended to avoid direct backups of hot indexes. Instead, rely on Splunk's inherent replication capabilities to ensure data durability.
• Warm Indexes:
  • Challenges: While not as volatile as hot indexes, warm indexes still see significant read activity. They are rotated data sets are no longer written to, and therefore can be backed up effectively via traditional backup solutions, but are still readily searchable.
  • Considerations: Periodic snapshots of warm indexes, especially for critical data, can be a good idea.
• Cold Indexes:
  • Challenges: Cold indexes are older, archived data that has been rolled out from the warm phase, typically onto slower, less expensive storage. Their sheer size can make backups lengthy and storage-intensive.
  • Considerations: Given that cold indexes are stable (no new data is written here), it's feasible to employ traditional backup methods. A complete backup of all cold indexes ensures a safeguard against any unforeseen data loss. Additionally, consider storage solutions that are both cost-effective and reliable for these larger backups.
• Thawed and Frozen Indexes: While not part of the standard data lifecycle in the same way, it's worth noting thawed and frozen indexes when discussing backup strategies.
  • Thawed Indexes: These are resurrected cold indexes, brought back for specific reasons, like a particular investigation or analysis.
  • Frozen Indexes: Data in this state is effectively considered disposable by the Splunk platform. Before data transitions to the frozen state, ensure you've made the necessary backups if retention is required.

When crafting a traditional backup strategy, you should understand the distinct characteristics and challenges associated with each index state. It informs not only the backup methods employed but also the frequency, storage considerations, and recovery strategies to ensure the optimal safeguarding of your Splunk data.

Configuration backup

Splunk configurations dictate how the platform behaves, ingests and processes data, and visualizes your data. If these configurations are lost or corrupted, you might end up with disrupted services, data ingestion issues, or inaccurate insights. Consider scheduled backups to ensure resilience for your core configurations. These backups should be stored in secure and redundant storage solutions. Don’t just trust that your backups happened, even if the jobs show as successful. Periodically validate the backups and ensure integrity and completeness.

Helpful resources

This article is part of the Splunk Outcome Path, Establishing disaster recovery and business continuity. Click into that path to continue building a plan for catastrophic failures to ensure a smooth recovery process.

In addition, these resources might help you implement the guidance provided in this article:

• Splunk Docs: The basics of indexer cluster architecture
• Splunk Docs: Multisite indexer cluster architecture
• Splunk Docs: How clustered indexing works
• Data Descriptor: Backup data
• Data Descriptor: GitLab
• Splunk Success Framework: Managing backup and restore processes
• Splunk Success Framework: Preparing for failures in the Splunk utility tier