Managing File Systems — S3QL 5.2.3 documentation

# Managing File Systems

The `s3qladm` command performs various operations on unmounted S3QL file systems. The file system must not be mounted when using `s3qladm` or things will go wrong badly.

The syntax is

    s3qladm [options] <action> <storage-url>

where `action` may be either of passphrase, restore-metadata, clear, recover-key or upgrade.

The s3qladm accepts the following general options, no matter what specific action is being invoked:

> `--authfile <path>`

>   Read authentication credentials from this file (default: `~/.s3ql/authinfo2)`

> `--debug-modules <modules>`

>   Activate debugging output from specified modules (use commas to separate multiple modules, ‘all’ for everything). Debug messages will be written to the target specified by the `--log` option.

> `--debug`

>   Activate debugging output from all S3QL modules. Debug messages will be written to the target specified by the `--log` option.

> `--quiet`

>   be really quiet

> `--log <target>`

>   Destination for log messages. Specify `none` for standard output or `syslog` for the system logging daemon. Anything else will be interpreted as a file name. Log files will be rotated when they reach 1 MiB, and at most 5 old log files will be kept. Default: `None`

> `--backend-options <options>`

>   Backend specific options (separate by commas). See backend documentation for available options.

> `--cachedir <path>`

>   Store cached data in this directory (default: `~/.s3ql)`

> `--version`

>   just print program version and exit

Hint: run `s3qladm <action> --help` to get help on the additional arguments that the different actions take.

## Changing the Passphrase

To change the passphrase of a file system, use the `passphrase` subcommand:

    s3qladm passphrase  <storage url>

This will not actually re-encrypt all the stored data with the new passphrase. Rather, S3QL generates an internal “master key” when the file system is created and uses this key to encrypt all stored data. The user-supplied passphrase is used to encrypt/decrypt only the master key, and can therefore be changed. This means, however, that if a passphrase has been disclosed to someone untrusted, changing it afterwards will not revoke access to people who had access to the old passphrase (because they could have decrypted the master key and retained a copy).

## Recovering the master key

If you’ve been extremely unlucky, then it is possible that a bug in S3QL or data-loss by your storage provider has resulted in object that holds the filesystem master key becoming inaccessible. In this case, knowing the passphrase does not help, as there is no master key to decrypt with it.

If you have also been diligent, then you can restore the master key from the external copy that mkfs.s3ql has asked you to make on filesystem creation time:

    s3qladm recover-key <storage url>

## Restoring Metadata Backups

If the most-recent copy of the file system metadata has been damaged irreparably, it is possible to restore one of the automatically created backup copies.

The command

    s3qladm restore-metadata <storage url>

will give you a list of the available metadata backups and allow you to select one to restore.

Warning

You should probably not use this functionality without having asked for help on the mailing list first (see Further Resources / Getting Help).

## Deleting a file system

A file system can be deleted with:

    s3qladm clear <storage url>

This physically deletes all the data and file system structures.

## Upgrading the file system

If you have installed a new version of S3QL, it may sometimes be necessary to upgrade the file system metadata as well. After this operation, the file system can no longer be accessed with older versions of S3QL.

During the upgrade you have to make sure that the command is not interrupted, and that no one else tries to mount, check or upgrade the file system at the same time.

To upgrade a file system from the previous to the current revision, execute

    s3qladm upgrade <storage url>