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

# Block Rotation

> How SKALE keeps nodes lightweight while preserving historical access

Block rotation on a SKALE Chain limits the disk space used by consensus and full-sync nodes by pruning old blocks, ensuring efficient storage and performance.

## Storage Allocation

Each SKALE Chain reserves **12.6 GB** of storage for core blockchain data on consensus and full-sync nodes. This includes:

* `blocks`
* `transactions` and their receipts
* `log blooms` (for efficient event filtering)
* `"best"` — latest block info (`lastBlockHash`)
* `"chainStart"` — earliest available block (`firstBlockHash`, useful after importing snapshots)

<Note>
  Block rotation does not apply to **SKALE Archive Nodes** or **SKALE Indexer Nodes**, which both store the full block history.
</Note>

## How Block Rotation Works

To stay within the 12.6 GB limit, SKALE Chains maintain a dynamic range of block data:

* Only the **most recent 80–100%** of data is retained.
* The **oldest 20%** is pruned as new blocks are added.
* The rotation is based on **data size**, not block count.

### Example

If block storage nears the 12.6 GB cap:

* The chain deletes the oldest blocks until usage returns to \~80% of the cap.
* Only recent blocks remain accessible on consensus and full-sync nodes.

This sliding-window model ensures that the chain operates efficiently without growing indefinitely in size.

## Benefits

* **Efficient resource use** — prevents storage bloat.
* **High performance** — reduces read/write overhead.
* **Scalability** — supports many lightweight SKALE Chains running in parallel.

## Full Historical Access

If your app or service requires the entire blockchain history (e.g. for analytics, block explorers, or archival indexing), use a **SKALE Archive Node**, which:

* Stores all past blocks
* Maintains full transaction and log history
* Is not affected by block rotation

Want to run a SKALE Archive Node or build on top of historical data? Reach out on [SKALE's Discord](https://discord.gg/skale) or explore the [developer docs](/validators/run-archive-node).

## API Changes

| Calls                                     | Changes                                          |
| ----------------------------------------- | ------------------------------------------------ |
| eth\_getBlockByNumber/eth\_getBlockByHash | may return null                                  |
| eth\_getBlockTransactionCountByNumber     | may return null                                  |
| eth\_getBlockTransactionCountByHash       | may return null                                  |
| eth\_getUncleCountByBlockNumber           | may return null                                  |
| eth\_getUncleCountByBlockHash             | may return null                                  |
| eth\_getTransactionByBlockHashAndIndex    | may return null                                  |
| eth\_getTransactionByBlockNumberAndIndex  | may return null                                  |
| eth\_getUncleByBlockHashAndIndex          | may return null                                  |
| eth\_getUncleByBlockNumberAndIndex        | may return null                                  |
| eth\_getTransactionByHash                 | may return null                                  |
| eth\_getTransactionReceipt                | may return null                                  |
| eth\_getFilterLogs                        | will treat removed blocks as if they have 0 logs |
| eth\_getLogs                              | will treat removed blocks as if they have 0 logs |