> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pg-sharding.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Shard

A **shard** is a portion of data stored within a cluster. A cluster is made up of multiple shards, each containing a unique subset of the overall dataset. Together, these shards form the complete data store.

**Shard management** includes tasks like:

* Replication
* Backup
* Failover/switchover configuration
* Monitoring

These tasks are the responsibility of the **user**, not SPQR.

SPQR was originally designed to enable PostgreSQL sharding on top of managed cloud database services. While it simplifies query routing across shards, it does not aim to be a complete shard management system. There are **no current plans** to release a fully open-source shard management solution as part of SPQR.

Instead, users are encouraged to build PostgreSQL clusters using established high-availability (HA) tools such as:

* **Patroni**
* **PgConsul**
* **Stolon**
* **Managed PostgreSQL offerings**

These tools rely on physical quorum-based HA mechanisms, which are proven to be reliable and compatible with SPQR.

Importantly, **SPQR does not manage or control the individual shards**. It only requires:

* Connection information for each shard
* The data range assigned to each shard

That's all SPQR needs to route queries correctly.