# Cloud Compute limits

> The limits on instance sizes, snapshots, backups, names and API calls, in one place.

Source: https://www.coritan.com/docs/cloud-compute/limits/

This page lists every fixed limit on a Cloud Compute instance. The plan sets the rest, and the page that covers each feature explains how to work within it.

## Size

The size you order sets each instance's vCPU, memory, disk and monthly traffic allowance. The **Billing** tab shows the plan, and the order page shows what each size includes.

| What | Limit |
| --- | --- |
| Changing size | Not possible on an existing instance. Move to a new instance of the size you want. |
| Changing plan | Only to another billing period of the same size. |
| Traffic allowance | Counted per calendar month, in both directions. One TB is 1024⁴ bytes. |

[Change an instance's plan or cancel it](/docs/cloud-compute/billing/) covers plan changes and moving to another size, and [How instance traffic is counted](/docs/cloud-compute/traffic/) covers the allowance.

## Snapshots and backups

| What | Limit |
| --- | --- |
| Snapshots per instance | 8. A snapshot that failed does not count. |
| Snapshot name | Starts with a letter, then letters, digits, hyphens and underscores. Keep it to 37 characters: the form and the API accept 40, but a longer name fails when we take the snapshot. |
| Snapshot description | 255 characters in the dashboard. |
| Backups per instance | 16. |
| Backup note | 255 characters. |
| Backup jobs at once | One per instance: a backup, a restore or a deletion. |
| New backups once the traffic allowance is used up | Blocked until the next month. Restores and deletions still work. |

[Take and roll back instance snapshots](/docs/cloud-compute/snapshots/) and [Back up and restore an instance](/docs/cloud-compute/backups/) explain each one.

## Names

| What | Limit |
| --- | --- |
| Hostname when you order | Letters, digits, hyphens and dots, up to 100 characters. Each part between dots is at most 63 characters. |
| Hostname on the **Access** and **Settings** tabs | One label of letters, digits and hyphens, up to 63 characters, with no hyphen at the start or end. |
| Name on the **Network** tab | A full name in a zone you hold, from 3 to 253 characters. |
| Reverse DNS name | A full name, up to 253 characters. |

## Console

| What | Limit |
| --- | --- |
| Time to connect | 120 seconds from the start of a session. The dashboard asks for a new session each time it connects. |
| Consoles open at once | Limited per account. A console over the limit does not connect, and its socket closes with code `4029`. Close a console you no longer use and try again. |

## Rate limits

We count these actions per account and per instance. Each limit covers a rolling window.

| Action | Most per window | Window |
| --- | --- | --- |
| Power actions: start, stop, shut down and restart | 24 | 60 seconds |
| New backups | 8 | 5 minutes |
| Backup restores | 8 | 5 minutes |
| Rebuilds | 8 | 10 minutes |

A request over the limit fails, and the dashboard shows `Too many requests for this action. Please wait and try again.` Through the API, the request answers `429`:

```json
{
  "detail": {
    "error": "rate_limited",
    "message": "Too many requests for this action. Please wait and try again.",
    "action": "vps.power",
    "retry_after_seconds": 60
  }
}
```

`action` is `vps.power`, `vps.backup`, `vps.backup_restore` or `vps.rebuild`. `retry_after_seconds` and the `Retry-After` header give the length of the window. A request refused this way does not count towards the limit.

Every API request also counts towards the limits for your account as a whole, which [Rate limits](/docs/api/rate-limits/) describes.

## Queries

| What | Limit |
| --- | --- |
| Graph time frame | `hour`, `day`, `week`, `month` or `year`. |
| Host tasks per request | 50 by default, 100 at most. |

## Related

- [Cloud Compute](/docs/cloud-compute/)
- [Rate limits](/docs/api/rate-limits/)
- [Troubleshoot instances](/docs/cloud-compute/troubleshooting/)