Appendix: Cluster sizes

Default Cluster Sizes

For self-managed Materialize, the cluster sizes are configured with the following default resource allocations:

Size	Scale	CPU Limit	Disk Limit	Memory Limit
`25cc`	`1`	`0.5`	`7762MiB`	`3881MiB`
`50cc`	`1`	`1`	`15525MiB`	`7762MiB`
`100cc`	`1`	`2`	`31050MiB`	`15525MiB`
`200cc`	`1`	`4`	`62100MiB`	`31050MiB`
`300cc`	`1`	`6`	`93150MiB`	`46575MiB`
`400cc`	`1`	`8`	`124201MiB`	`62100MiB`
`600cc`	`1`	`12`	`186301MiB`	`93150MiB`
`800cc`	`1`	`16`	`248402MiB`	`124201MiB`
`1200cc`	`1`	`24`	`372603MiB`	`186301MiB`
`1600cc`	`1`	`31`	`481280MiB`	`240640MiB`
`3200cc`	`1`	`62`	`962560MiB`	`481280MiB`
`6400cc`	`2`	`62`	`962560MiB`	`481280MiB`

Custom Cluster Sizes

When installing the Materialize Helm chart, you can override the default cluster sizes and resource allocations. These cluster sizes are used for both internal clusters, such as the system_cluster, as well as user clusters.

💡 Tip: In general, you should not have to override the defaults. At minimum, we recommend that you keep the 25-200cc cluster sizes.

operator:
  clusters:
    sizes:
      <size>:
        workers: <int>
        scale: 1                  # Generally, should be set to 1.
        cpu_exclusive: <bool>
        cpu_limit: <float>         # e.g., 6
        credits_per_hour: "0.0"    # N/A for self-managed.
        disk_limit: <string>       # e.g., "93150MiB"
        memory_limit: <string>     # e.g., "46575MiB"

Field	Type	Description	Recommendation
workers	int	The number of timely workers in your cluster replica.	Use 1 worker per CPU core, with a minimum of 1 worker.
scale	int	The number of pods (i.e., processes) to use in a cluster replica; used to scale out replicas horizontally. Each pod will be provisioned using the settings defined in the size definition.	Generally, this should be set to 1. This should only be greater than 1 when a replica needs to take on limits that are greater than the maximum limits permitted on a single node.
cpu_exclusive	bool	The flag that determines if the workers should attempt to pin to a particular CPU core.	Set to true if and only if the `cpu_limit` is a whole number and the CPU management policy in the k8s cluster is set to static.
cpu_limit	float	The k8s limit for CPU for a replica pod in cores.	Prefer whole number values to enable CPU affinity. Kubernetes only allows CPU Affinity for pods taking a whole number of cores. If the value is not a whole number, set `cpu_exclusive` to false.
memory_limit	float	The k8s limit for memory for a replica pod in bytes.	For most workloads, use an approximate 1:8 CPU-to-memory ratio (1 core 8 GiB). This can vary depending on your workload characteristics.
disk_limit	float	The size of the NVMe persistent volume to provision for a replica pod in bytes.	When spill-to-disk is enabled, use a 1:2 memory-to-disk ratio. Materialize spills data to disk when memory is insufficient, which can impact performance.
credits_per_hour	string	This is a cloud attribute that should be set to “0.00” in self-managed.	Set to “0.00” for self-managed deployments.

NOTE: If you have modified the default cluster size configurations, you can query the mz_cluster_replica_sizes system catalog table for the specific resource allocations.