---
title: File system backup and restoration
sidebar_label: File system
---

Though a majority of configuration is stored in [etcd](../core-components/etcd.md), there are several files and directories containing additional configuration stored under `/etc/sysconfig/deephaven`. File-on-disk configuration tends to be related to process startup, authentication, and additional JARs/classes on the classpath to extend Deephaven's functionality.

## Process startup configuration

Process startup override parameters such as heap are stored in `etc/sysconfig/deephaven/illumon.iris.hostconfig`. This file exists on each node within a cluster and may have different values for a given process between nodes. For example, the `tdcp` process on one node within the cluster may be assigned 6G of heap, whereas the `tdcp` process on a different node may be assigned 10G of heap.

If a custom tailer exists, configuration XML should be stored in `/etc/sysconfig/illumon.d/resources`, though this may vary between deployments.

## Authentication files

Many authentication keys and certificates are stored under `/etc/sysconfig/deephaven/auth` and `/etc/sysconfig/deephaven/auth-user`.

`/etc/sysconfig/deephaven/auth` is used to store sensitive certificates and keys, and should not be accessible to most users. Particular files of interest include:

- `priv-*.base64.txt`: These files contain system users' private keys, which allow key-based access to the system. If required, [new keys may be generated](../../sys-admin/configuration/public-and-private-keys.md) for users.
- [`/etc/sysconfig/deephaven/auth/dsakeys.txt`](../configuration/public-and-private-keys.md#authorized-keys-file-configuration): If you have enabled text-file based key authentication (not enabled by default), `dsakeys.txt` may be used to define key-based authentication for users. This file may be empty or missing if public keys are stored in the ACL store (etcd or MySQL).
- [`/etc/sysconfig/deephaven/auth/authusers.txt`](../configuration/configuration-file-locations-overview.md#authuserstxt): This file will exist if you have enabled text-file password-based authentication (not enabled by default).
- Any custom certificate files needed for authentication with external services such as LDAP are stored in `/etc/sysconfig/deephaven/illumon.d.latest/resources/`.

> [!NOTE]
> It is a good safety measure to back up all of `/etc/sysconfig/deephaven/auth` to ensure that needed keys and passphrase files are available in case they are later needed for restore operations.

The `/etc/sysconfig/deephaven/auth-user` directory is used to store the `webServices-keystore.p12` certificate used by the web service, and is generally visible to all Deephaven `query` and `merge` processes. Copying this file to a different cluster is not recommended because it may be hostname-specific. Instead, a new certificate should be used (or generated) during the installation of the new cluster.

## Plugins and custom jars

Deephaven is highly customizable, and installations may have customized JARs/classes and plugins that extend the functionality of the system. Generally speaking, customized JARs and classes will be in `/etc/sysconfig/deephaven/illumon.d.latest/java_lib/`.

Plugins should not be copied between Deephaven instances; instead, they should be re-installed and re-activated in the new environment. Activated plugins can be seen in `/etc/sysconfig/deephaven/illumon.d.latest/plugins/`.

## Related documentation

- [Backup, Restore, and Migration overview](./backup-and-restore.md)
- [etcd and MySQL backup and restore](./etcd-and-acls-backup.md)
- [Configuration backup and restore](./configuration-properties-backup.md)
- [WorkspaceData backup and restore](./workspace-data-backup.md)
- [Table migration](./table-migration.md)