Configuration Recommendations for MariaDB Xpand


This page is a list of Best Practices for when setting up and installing Xpand. For additional information about how to complete the initial installation and general configuration instructions, see "Deploy Xpand Topology".

Network Configuration

IP addressing and Hostnames

When setting up a new cluster it is best to maintain consistent ordering and numbering with IP address, hostnames, and node numbers.

For example:

  • IP Address x.x.x.11 = hostname1 = node 1.

  • IP Address x.x.x.12 = hostname2 = node 2.

  • IP Address x.x.x.13 = hostname3 = node 3.

Currently, to achieve this, you have to add nodes one at a time to the cluster using the ALTER CLUSTER ADD statement or XpandGUI's Flex page. Otherwise, the node number is random as the numbers are assigned in the order that the nodes respond to the addition request.


This is only relevant for on-premises installations, as you don't typically have that much control over IP address allocation in cloud/hosted environments.

Multi-homed Network Configuration

While Xpand runs fine on nodes with a single network connection, the recommended network topology is a setup with at least two ethernet connections; the front-end and back-end. The front-end ethernet is for external traffic to communicate with the cluster while the back-end ethernet should be used for internode communication only.

  • By default, the database will listen on all addresses and so no additional settings will be needed for the front-end ethernet.

  • The IP of the Back-end ethernet will need to be set using the initial software setup wizard and is listed as "8 - Private (Back-End) IP: x.x.x.x".

For additional information, see "Firewalls for MariaDB Xpand".


When adding nodes to a cluster in a cloud environment such as AWS or Rackspace it is important to use the internal IP address as using the external address can cause cluster creation to fail.

Network Security

The 3 main approaches to network security with MariaDB Xpand are as follows:

  • You are in a secured/trusted environment, so iptables is not needed. (Recommended)

  • You are in a hosted cloud environment such as AWS, where Security Group or similar mechanisms provide IP security by limiting access to ports (thus iptables on each node would be redundant).

  • Neither of the above, use iptables to properly secure the cluster.

In a typical secure configuration, you will limit access to TCP Ports 80, 8080, and 22 to the network CIDR range that maps to the public IPs for your administrative clients (typically exposed through your firewall), and you will limit access to TCP Port 3306 to your administrative client CIDR range and also to the range of IPs used by your application servers (if they are outside your firewall).

For additional information, see "Firewalls for MariaDB Xpand".

Front-end Load Balancing

Xpand has been designed to take full advantage of a front-end load balancer. For additional information, see "MariaDB MaxScale".


NTP should be running so that the nodes' clocks do not get out of sync; otherwise, you may get inconsistent timestamps when using now() , and this also makes log analysis much more difficult. For additional information, see "Chronyd for Clock Synchronization with MariaDB Xpand".

Managing Internode SSH Access

There are three methods of internode SSH access, listed here in order of administrative simplicity:

  1. Host Based Authentication. The Xpand installer will set up host based authentication if allowed. (This is Recommended.)

  2. Key Pair Authentication. For additional information, see "SSH Configuration".

  3. Password.


If you use password-based authentication then the clx command-line utility will require a password for most commands.

For ease of use, we suggest having the same password for each node.


Databases are not typically network-bound (as compared to a file server), however, a clustered database system does rely upon low latency links between nodes.

  • Cluster nodes should always be on the same subnet, with no intermediate routers between. As mentioned above, a dedicated backend connection is ideal.

For additional information, see "Measure Platform Limits with MariaDB Xpand".

Storage Configuration


  • As with MySQL, disk seeks can be a huge performance bottleneck, and as such we require Xpand data to be on local SSDs rather than on spinning disk.

  • To efficiently use your SSDs, and also avoid log build-up filling your data directory, it is suggested that a single large spinning disk be allocated for the log files. The path for the logs folder is /data/clustrix/log/.

For additional information, see "Measure Platform Limits with MariaDB Xpand".


Below are some general best practices on RAID configuration for Xpand:

  • RAID 0: For best performance, it is recommended to use RAID 0 and in the case of a failed disk rely on node level redundancy.

  • RAID 5: Due to the performance hit for running RAID, it is not a supported configuration.

  • RAID 10: Often chosen for redundancy (without the performance loss of RAID5), but as Xpand already offers data redundancy, Raid 0 is sufficient for most deployments.

File System

For optimal performance use the ext4 format for your filesystem.

Xpand will work when using an ext3 formatted volume, but it will generate warnings during startup and space allocation. Growing an ext3 device file will take longer than with other volume formats.

You can see which format your filesystem is with the following:

shell> # df -T
Filesystem    Type   1K-blocks       Used  Available Use% Mounted on
/dev/md1      ext3    14446128    2253276   11459028  17% /
tmpfs        tmpfs    16440012     131076   16308936   1% /dev/shm
/dev/md0      ext3      253807      27521     213182  12% /boot
/dev/md3      ext4  1060589952  993662712   13052376  99% /data/clustrix
/dev/sdh1     ext3   484535504    9458888  450657416   3% /data/clustrix/log

In the above example, we have most of the partitions running ext3 and the main /data partition running ext4.

Operating System Concerns


Below are the general operating system best practices and concerns for running the Xpand software.

  • Xpand supports deployment on CentOS/RHEL 7.4+.

  • You should always avoid running 3rd party software on a node that is running Xpand as the database expects to be able to use the majority of the system resources. Running 3rd party software can cause a node to behave in unexpected ways and is not officially supported. Running 3rd party software that makes heavy use of CPU can result in "slow kernel scheduling" warning messages, and if severe enough, can lead to group changes.

  • It is recommended to add the following path to your user PATH: /opt/clustrix/bin. This will allow you to run clx command-line utility with ease.

  • There are several useful commands in The CLX Command-Line Administration Tool that can make administering a cluster much easier.


Do not configure swap. Having the database process go to swap, even on SSD, will degrade performance.


  • Shared CPU/Core architecture should be avoided if possible as the database is quite sensitive to wait time when attempting to access a core. Dedicated CPU/Cores are highly recommended.

  • VMs on the same physical box may result in I/O contention especially if they're all trying to do bulk inserts.