borgmatic/docs/how-to/deal-with-very-large-backups.md

---
title: How to deal with very large backups
eleventyNavigation:
  key: Deal with very large backups
  parent: How-to guides
  order: 3
---
## Biggish data

Borg itself is great for efficiently de-duplicating data across successive
backup archives, even when dealing with very large repositories. But you may
find that while borgmatic's default mode of "prune, create, and check" works
well on small repositories, it's not so great on larger ones. That's because
running the default pruning and consistency checks take a long time on large
repositories.

### A la carte actions

If you find yourself in this situation, you have some options. First, you can
run borgmatic's pruning, creating, or checking actions separately. For
instance, the the following optional actions are available:

```bash
borgmatic prune
borgmatic create
borgmatic check
```

(No borgmatic `prune`, `create`, or `check` actions? Try the old-style
`--prune`, `--create`, or `--check`. Or upgrade borgmatic!)

You can run with only one of these actions provided, or you can mix and match
any number of them in a single borgmatic run. This supports approaches like
skipping certain actions while running others. For instance, this skips
`prune` and only runs `create` and `check`:

```bash
borgmatic create check
```

Or, you can make backups with `create` on a frequent schedule (e.g. with
`borgmatic create` called from one cron job), while only running expensive
consistency checks with `check` on a much less frequent basis (e.g. with
`borgmatic check` called from a separate cron job).


### Consistency check configuration

Another option is to customize your consistency checks. The default
consistency checks run both full-repository checks and per-archive checks
within each repository.

But if you find that archive checks are too slow, for example, you can
configure borgmatic to run repository checks only. Configure this in the
`consistency` section of borgmatic configuration:

```yaml
consistency:
    checks:
        - repository
```

Here are the available checks from fastest to slowest:

 * `repository`: Checks the consistency of the repository itself.
 * `archives`: Checks all of the archives in the repository.
 * `extract`: Performs an extraction dry-run of the most recent archive.
 * `data`: Verifies the data integrity of all archives contents, decrypting and decompressing all data (implies `archives` as well).

See [Borg's check documentation](https://borgbackup.readthedocs.io/en/stable/usage/check.html) for more information.

If that's still too slow, you can disable consistency checks entirely,
either for a single repository or for all repositories.

Disabling all consistency checks looks like this:

```yaml
consistency:
    checks:
        - disabled
```

Or, if you have multiple repositories in your borgmatic configuration file,
you can keep running consistency checks, but only against a subset of the
repositories:

```yaml
consistency:
    check_repositories:
        - path/of/repository_to_check.borg
```

Finally, you can override your configuration file's consistency checks, and
run particular checks via the command-line. For instance:

```bash
borgmatic check --only data --only extract
```

This is useful for running slow consistency checks on an infrequent basis,
separate from your regular checks.


## Troubleshooting

### Broken pipe with remote repository

When running borgmatic on a large remote repository, you may receive errors
like the following, particularly while "borg check" is validating backups for
consistency:

```text
    Write failed: Broken pipe
    borg: Error: Connection closed by remote host
```

This error can be caused by an ssh timeout, which you can rectify by adding
the following to the `~/.ssh/config` file on the client:

```text
    Host *
        ServerAliveInterval 120
```

This should make the client keep the connection alive while validating
backups.