Administrator's Guide


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Administrator's Guide


The text and illustrations in this document are licensed under the terms of the GNU Affero General Public License Version 3 as published by the Free Software Foundation. See the GNU Affero General Public License ( for more details.

Many of the core VoltDB database features described herein are part of the VoltDB Community Edition, which is licensed under the GNU Affero Public License 3 as published by the Free Software Foundation. Other features are specific to the VoltDB Enterprise Edition and VoltDB Pro, which are distributed by VoltDB, Inc. under a commercial license.

The VoltDB client libraries, for accessing VoltDB databases programmatically, are licensed separately under the MIT license.

Your rights to access and use VoltDB features described herein are defined by the license you received when you acquired the software.

VoltDB is a trademark of VoltDB, Inc.

VoltDB software is protected by U.S. Patent Nos. 9,600,514, 9,639,571, 10,067,999, 10,176,240, and 10,268,707. Other patents pending.


This books explains how to create and manage VoltDB databases and the clusters that run them.

Table of Contents

1. Structure of This Book
2. Related Documents
1. Managing VoltDB Databases
1.1. Getting Started
1.2. Understanding the VoltDB Utilities
1.3. Management Tasks
2. Preparing the Servers
2.1. Server Checklist
2.2. Install Required Software
2.3. Configure Memory Management
2.3.1. Disable Swapping
2.3.2. Disable Transparent Huge Pages
2.3.3. Enable Virtual Memory Mapping and Overcommit
2.4. Turn off TCP Segmentation
2.5. Configure Time Services
2.6. Increase Resource Limits
2.7. Configure the Network
2.8. Assign Network Ports
2.9. Eliminating Server Process Latency
3. Starting and Stopping the Database
3.1. Configuring the Cluster and Database
3.2. Initializing the Database Root Directory
3.3. Starting the Database
3.4. Loading the Database Definition
3.5. Stopping the Database
3.6. Restarting the Database
3.7. Starting and Stopping Individual Servers
4. Maintenance and Upgrades
4.1. Backing Up the Database
4.2. Updating the Database Schema
4.2.1. Performing Live Schema Updates
4.2.2. Performing Updates Using Save and Restore
4.3. Upgrading the Cluster
4.3.1. Performing Server Upgrades
4.3.2. Performing Rolling Hardware Upgrades on K-Safe Clusters
4.3.3. Adding Servers to a Running Cluster with Elastic Scaling
4.3.4. Removing Servers from a Running Cluster with Elastic Scaling
4.3.5. Reconfiguring the Cluster During a Maintenance Window
4.4. Upgrading VoltDB Software
4.4.1. Upgrading VoltDB Using Save and Restore
4.4.2. Upgrading Older Versions of VoltDB Manually
4.4.3. Upgrading VoltDB With Reduced Downtime Using a DR Replica
4.4.4. Performing an Online Upgrade Using Multiple XDCR Clusters
4.4.5. Performing an Online Upgrade With Limited Hardware
4.4.6. Downgrading, or Falling Back to a Previous VoltDB Version
4.5. Updating the VoltDB Software License
5. Monitoring VoltDB Databases
5.1. Monitoring Overall Database Activity
5.1.1. VoltDB Management Center
5.1.2. System Procedures
5.1.3. SNMP Alerts
5.2. Setting the Database to Read-Only Mode When System Resources Run Low
5.2.1. Monitoring Memory Usage
5.2.2. Monitoring Disk Usage
5.3. Integrating VoltDB with Other Monitoring Systems
5.3.1. Integrating with Prometheus
5.3.2. Integrating with Nagios
5.3.3. Integrating with New Relic
6. Logging and Analyzing Activity in a VoltDB Database
6.1. Introduction to Logging
6.2. Creating the Logging Configuration File
6.3. Enabling Logging for VoltDB
6.4. Changing the Timezone of Log Messages
6.5. Changing the Configuration on the Fly
7. What to Do When Problems Arise
7.1. Where to Look for Answers
7.2. Handling Errors When Restoring a Database
7.2.1. Logging Constraint Violations
7.2.2. Safe Mode Recovery
7.3. Collecting the Log Files
A. Server Configuration Options
A.1. Server Configuration Options
A.1.1. Network Configuration (DNS)
A.1.2. Time Configuration
A.2. Process Configuration Options
A.2.1. Maximum Heap Size
A.2.2. Other Java Runtime Options (VOLTDB_OPTS)
A.3. Database Configuration Options
A.3.1. Sites per Host
A.3.2. K-Safety
A.3.3. Network Partition Detection
A.3.4. Automated Snapshots
A.3.5. Import and Export
A.3.6. Command Logging
A.3.7. Heartbeat
A.3.8. Temp Table Size
A.3.9. Query Timeout
A.3.10. Flush Interval
A.3.11. Long-Running Process Warning
A.4. Path Configuration Options
A.4.1. VoltDB Root
A.4.2. Snapshots Path
A.4.3. Export Overflow Path
A.4.4. Command Log Path
A.4.5. Command Log Snapshots Path
A.5. Network Ports
A.5.1. Client Port
A.5.2. Admin Port
A.5.3. Web Interface Port (http)
A.5.4. Internal Server Port
A.5.5. Replication Port
A.5.6. Zookeeper Port
A.5.7. TLS/SSL Encryption (Including HTTPS)
B. Snapshot Utilities
snapshotconvert — Converts the tables in a VoltDB snapshot into text files.
snapshotverifier — Verifies that the contents of one or more snapshot files are complete and usable.