Init - Preparing a new repository

The place where your backups will be saved is called a “repository”. This chapter explains how to create (“init”) such a repository. The repository can be stored locally, or on some remote server or service. We’ll first cover using a local repository; the remaining sections of this chapter cover all the other options. You can skip to the next chapter once you’ve read the relevant section here.

For automated backups, rustic accepts the repository location in the environment variable RUSTIC_REPOSITORY.

For the password, several options exist:

• Setting the environment variable RUSTIC_PASSWORD

• Specifying the path to a file with the password via the option --password-file or the environment variable RUSTIC_PASSWORD_FILE

• Configuring a program to be called when the password is needed via the option --password-command or the environment variable RUSTIC_PASSWORD_COMMAND

The init command has an option called --set-version which can be used to explicitly set the version for the new repository.

The below table shows which rustic version is required to use a certain repository version and shows new features introduced by the repository format.

Moreover, there are different options which can be set when initializing a repository:

Options to specify the target pack size:

• --set-treepack-size, --set-datapack-size specify the default target pack size for tree and data pack files. Arguments can given using TODO For example, valid sizes are “4048kiB”, “2MB”, “30MiB”, etc. If not specified, the default is 4 MiB for tree packs and 32 MiB for data packs.

• --set-treepack-growfactor, --set-datapack-growfactor specify how much the target pack size should be increased per square root of the total pack size in bytes of the given type. This equals to 32kiB per square root of the total pack size in GiB.

Note that larger pack sizes have advantages, especially for large repository or remote repositories. They lead to less packs in the repository and transfer larger datasets to the repository which can increase the throughput. But there are also disadvantages. Rustic keeps the whole pack in memory before writing it to the backend. As writes are parallelized, multiple packs are kept. So larger pack sizes increase the memory usage of the backup command. Moreover larger pack sizes lead to increased repack rates during prune or forget --prune.