# Planning Architecture and Nodes > How many nodes? Which modules need HA? How to plan based on available resources and requirements? --- LLMS index: [llms.txt](/llms.txt) --- Pigsty uses a [**modular architecture**](/docs/concept/arch). You can combine modules like building blocks and express your intent through [**declarative configuration**](/docs/concept/iac). ## Common Patterns Here are common deployment patterns for reference. Customize based on your requirements: | Pattern | [**INFRA**](/docs/infra/) | [**ETCD**](/docs/etcd/) | [**PGSQL**](/docs/pgsql/) | [**MINIO**](/docs/minio) | Description | |:----------------------------------------------------:|:-------------------------:|:-----------------------:|:-------------------------:|:------------------------:|---------------------------------------------------------------| | Single-node ([**`meta`**](/docs/conf/meta)) | 1 | 1 | 1 | | [**Single-node deployment**](/docs/setup/install) default | | Slim deploy ([**`slim`**](/docs/conf/slim)) | | 1 | 1 | | Database only, no monitoring infra | | Infra-only ([**`infra`**](/docs/conf/infra)) | 1 | | | | Monitoring infrastructure only | | Rich deploy ([**`rich`**](/docs/conf/rich)) | 1 | 1 | 1 | 1 | Single-node + object storage + local repo with all extensions | {.full-width} | Multi-node Pattern | [**INFRA**](/docs/infra/) | [**ETCD**](/docs/etcd/) | [**PGSQL**](/docs/pgsql/) | [**MINIO**](/docs/minio) | Description | |:------------------------------------------:|:-------------------------:|:-----------------------:|:-------------------------:|:------------------------:|------------------------------------------| | Two-node ([**`dual`**](/docs/conf/dual)) | 1 | 1 | 2 | | Semi-HA, tolerates specific node failure | | Three-node ([**`trio`**](/docs/conf/trio)) | 3 | 3 | 3 | | Standard HA, tolerates any one failure | | Four-node ([**`full`**](/docs/conf/full)) | 1 | 1 | 1+3 | | Demo setup, single INFRA/ETCD | | Production ([**`simu`**](/docs/conf/simu)) | 2 | 3 | n | n | 2 INFRA, 3 ETCD | | Large-scale (custom) | 3 | 5 | n | n | 3 INFRA, 5 ETCD | {.full-width} Your architecture choice depends on reliability requirements and available resources. Serious production deployments require at least **3** nodes for [**HA configuration**](#three-node-setup). With only **2** nodes, use [**Semi-HA configuration**](#two-node-setup). > [!NOTE] Expert Consulting: Architecture Planning > We offer [**Architecture Consulting Services**](https://pigsty.io/price) to help plan your Pigsty configuration. -------- ## Trade-offs - Pigsty monitoring requires at least **1** INFRA node. Production typically uses **2**; large-scale deployments use **3**. - PostgreSQL HA requires at least **1** ETCD node. Production typically uses **3**; large-scale uses **5**. Even-member clusters work, but do not tolerate more failures than an odd cluster with one fewer member, so prefer odd sizes. - Silo object storage through the MINIO module requires at least **1** [**MINIO node**](/docs/minio/config#single-node-single-disk). Production typically uses 4+ nodes in [**MNMD**](/docs/minio/config#multi-node-multi-disk) clusters. - Production PG clusters typically use at least two-node primary-replica configuration; serious deployments use 3 nodes; high read loads can have dozens of replicas. - For PostgreSQL, you can also use advanced configurations: offline instances, sync instances, standby clusters, delayed clusters, etc. -------- ## Single-Node Setup The simplest configuration with everything on a single node. Installs four essential modules by default. Typically used for demos, devbox, or testing. | ID | [NODE](/docs/node/) | [PGSQL](/docs/pgsql/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | |:--:|:-------------------:|:---------------------:|:---------------------:|:-----------------------:| | 1 | `node-1` | `pg-meta-1` | `infra-1` | `etcd-1` | {.full-width} With an external S3/MinIO [**backup repository**](/docs/pgsql/backup/) providing RTO/RPO guarantees, this configuration works for standard production environments. Single-node variants: - **Rich** ([**`rich`**](/docs/conf/rich)): Production single-node template with local Silo object storage, local software repo, and all PG extensions. - **Slim** ([**`slim`**](/docs/conf/slim)): Installs only [**PGSQL**](/docs/pgsql/) and [**ETCD**](/docs/etcd/), no monitoring infra. [**Slim installation**](/docs/setup/slim) can expand to [**multi-node HA deployment**](/docs/setup/slim#ha-cluster). - **Infra-only** ([**`infra`**](/docs/conf/infra)): Opposite of slim—installs only [**INFRA**](/docs/infra/) monitoring infrastructure, no database services, for monitoring other instances. - **Alternative kernels**: Replace vanilla PG with derivatives: [**`pgsql`**](/docs/conf/pgsql/), [**`mssql`**](/docs/conf/mssql/), [**`polar`**](/docs/conf/polar/), [**`ivory`**](/docs/conf/ivory/), [**`mysql`**](/docs/conf/mysql/), [**`pgtde`**](/docs/conf/pgtde/), [**`oriole`**](/docs/conf/oriole/), [**`agens`**](/docs/conf/agens/), [**`pgedge`**](/docs/conf/pgedge/). -------- ## Two-Node Setup [**Two-node configuration**](/docs/conf/dual) enables database replication and **Semi-HA** capability with better data redundancy and limited failover support: | ID | [NODE](/docs/node/) | [PGSQL](/docs/pgsql/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | |:--:|:-------------------:|:-----------------------:|:---------------------:|:-----------------------:| | 1 | `node-1` | `pg-meta-1` (`replica`) | `infra-1` | `etcd-1` | | 2 | `node-2` | `pg-meta-2` (`primary`) | | | {.full-width} Two-node HA auto-failover has limitations. This "Semi-HA" setup only auto-recovers from specific node failures: - If `node-1` fails: No automatic failover—requires manual promotion of `node-2` - If `node-2` fails: Automatic failover works—`node-1` auto-promoted -------- ## Three-Node Setup [**Three-node template**](/docs/conf/trio) provides true baseline HA configuration, tolerating any single node failure with automatic recovery. | ID | [NODE](/docs/node/) | [PGSQL](/docs/pgsql/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | |:--:|:-------------------:|:---------------------:|:---------------------:|:-----------------------:| | 1 | `node-1` | `pg-meta-1` | `infra-1` | `etcd-1` | | 2 | `node-2` | `pg-meta-2` | `infra-2` | `etcd-2` | | 3 | `node-3` | `pg-meta-3` | `infra-3` | `etcd-3` | {.full-width} -------- ## Four-Node Setup Pigsty [**Sandbox**](/docs/deploy/sandbox/) uses the [**standard four-node configuration**](/docs/conf/full). | ID | [NODE](/docs/node/) | [PGSQL](/docs/pgsql/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | |:--:|:-------------------:|:---------------------:|:---------------------:|:-----------------------:| | 1 | `node-1` | `pg-meta-1` | `infra-1` | `etcd-1` | | 2 | `node-2` | `pg-test-1` | | | | 3 | `node-3` | `pg-test-2` | | | | 4 | `node-4` | `pg-test-3` | | | {.full-width} For demo purposes, [**INFRA**](/docs/infra) / [**ETCD**](/docs/etcd) modules aren't configured for HA. You can adjust further: | ID | [NODE](/docs/node/) | [PGSQL](/docs/pgsql/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | [**MINIO**](/docs/minio/) | |:--:|:-------------------:|:---------------------:|:---------------------:|:-----------------------:|:-------------------------:| | 1 | `node-1` | `pg-meta-1` | `infra-1` | `etcd-1` | `minio-1` | | 2 | `node-2` | `pg-test-1` | `infra-2` | `etcd-2` | | | 3 | `node-3` | `pg-test-2` | | `etcd-3` | | | 4 | `node-4` | `pg-test-3` | | | | {.full-width} -------- ## More Nodes With proper virtualization infrastructure or abundant resources, you can [**use more nodes**](/docs/conf/simu) for **dedicated deployment** of each module, achieving optimal reliability, observability, and performance. | ID | [NODE](/docs/node/) | [INFRA](/docs/infra/) | [**ETCD**](/docs/etcd/) | [**MINIO**](/docs/minio/) | [PGSQL](/docs/pgsql/) | |:--:|:-------------------:|:---------------------:|:-----------------------:|:-------------------------:|:---------------------:| | 1 | `10.10.10.10` | `infra-1` | | | `pg-meta-1` | | 2 | `10.10.10.11` | `infra-2` | | | `pg-meta-2` | | 3 | `10.10.10.21` | | `etcd-1` | | | | 4 | `10.10.10.22` | | `etcd-2` | | | | 5 | `10.10.10.23` | | `etcd-3` | | | | 6 | `10.10.10.31` | | | `minio-1` | | | 7 | `10.10.10.32` | | | `minio-2` | | | 8 | `10.10.10.33` | | | `minio-3` | | | 9 | `10.10.10.34` | | | `minio-4` | | | 10 | `10.10.10.40` | | | | `pg-src-1` | | 11 | `10.10.10.41` | | | | `pg-src-2` | | 12 | `10.10.10.42` | | | | `pg-src-3` | | 13 | `10.10.10.50` | | | | `pg-test-1` | | 14 | `10.10.10.51` | | | | `pg-test-2` | | 15 | `10.10.10.52` | | | | `pg-test-3` | | 16 | ...... | | | | | {.full-width}