kopia/site/content/docs/FAQs/_index.md

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Frequently Asked Questions	Frequently Asked Questions	40

Questions

• What is a Snapshot?
• What is a Repository?
• What is a Policy?
• How to Restore My Backed Up Files/Directories?
• How Do I Enable Encryption?
• How Do I Enable Compression?
• How Do I Enable Data Deduplication?
• How Do I Change My Repository Password?
• What is a Kopia Repository Server?

Is your question not answered here? Please ask in the Kopia discussion forums for help!

Answers

What is a Snapshot?

A snapshot is a point-in-time backup of your files/directories; each snapshot contains the files/directories that you can restore when you need to.

What is a Repository?

A repository is the storage location where your snapshots are saved; Kopia supports cloud/remote, network, and local storage locations and all repositories are encrypted with a password that you designate.

See the repository help docs for more information.

What is a Policy?

A policy is a set of rules that tells Kopia how to create/manage snapshots; this includes features such as compression, snapshot retention, and scheduling when to take automatically snapshots.

How to Restore My Backed Up Files/Directories?

Files/directories are restored from the snapshots you create. To restore the data you backed up in a snapshot, Kopia gives you three options:

• mount the contents of a snapshot as a local disk so that you can browse and copy files/directories from the snapshot as if the snapshot is a local directory on your machine;

• restore all files/directories contained in a snapshot to any local or network location that you designate;

• or selectively restore individual files from a snapshot.

The Getting Started Guide provides directions on how to restore files/directions when using Kopia GUI and when using Kopia CLI.

How Do I Enable Encryption?

Encryption is at the repository level, and Kopia encrypts all snapshots in all repositories by default. You should have been asked for a password when you created your repository. That password is used to encrypt your backups. (Do not forget it, there is no way to recover the password!)

By default, Kopia uses the AES256-GCM-HMAC-SHA256 encryption algorithm for all repositories, but you can choose CHACHA20-POLY1305-HMAC-SHA256 if you want to. Picking an encryption algorithm is done when you initially create a repository. In KopiaUI, to pick the CHACHA20-POLY1305-HMAC-SHA256 encryption algorithm, you need to click the Show Advanced Options button at the screen where you enter your password when creating a new repository. For Kopia CLI users, you need to use the --encryption=CHACHA20-POLY1305-HMAC-SHA256 option when creating a repository with the kopia repository create command.

Currently, encryption algorithms cannot be changed after a repository has been created.

How Do I Enable Compression?

Compression is controlled by policies and is disabled by default. If compression is not working for a snapshot, it is likely that you have not enabled compression yet in your policy.

Enabling compression when using KopiaUI is easy; edit the policy you want to add compression to and pick a Compression Algorithm in the Compression section. Kopia CLI users need to use the kopia policy set command as shown in the Getting Started Guide. You can set compression on a per-source-directory basis...

kopia policy set </path/to/source/directory/> --compression=<deflate-best-compression|deflate-best-speed|deflate-default|gzip|gzip-best-compression|gzip-best-speed|pgzip|pgzip-best-compression|pgzip-best-speed|s2-better|s2-default|s2-parallel-4|s2-parallel-8|zstd|zstd-better-compression|zstd-fastest>

...or globally for all source directories:

kopia policy set --global --compression=<deflate-best-compression|deflate-best-speed|deflate-default|gzip|gzip-best-compression|gzip-best-speed|pgzip|pgzip-best-compression|pgzip-best-speed|s2-better|s2-default|s2-parallel-4|s2-parallel-8|zstd|zstd-better-compression|zstd-fastest>

If you enable or disable compression or change the compression algorithm, the new setting is applied going forward and not reteroactively. In other words, Kopia will not modify the compression for files/directories already uploaded to your repository.

How Do I Enable Data Deduplication?

Data deduplication is enabled automatically by Kopia for all repositories, regardless of whether you use the GUI or CLI. You do not need to do anything.

How Do I Change My Repository Password?

You must use Kopia CLI if you want to change your repository password; changing password is not currently supported via Kopia GUI. The kopia repository change-password command is used to change your password.

Before changing your password, you must be connected to your repository. This means that you can reset your password if you forget your password AND you are still connected to your repository. But this also means that you cannot reset your password if you forget your password and you are NOT still connected to your repository, because you will need your current password to connect to the repository.

Remember to select a secure repository password. The password is used to decrypt and access the data in your snapshots.

What is a Kopia Repository Server?

See the Kopia Repository Server help docs for more information.