BART has two main components and one optional component:
BART Rules File
You use the bart create command to take a file-level snapshot of a system at a particular time. The output is a catalog of files and file attributes called a manifest. The manifest lists information about all the files or specific files on a system. It contains information about attributes of files, which can include some uniquely identifying information, such as an MD5 checksum. For more information about the MD5 checksum, see the md5(3EXT) man page. A manifest can be stored and transferred between client and server systems.
BART does not cross file system boundaries, with the exception of file systems of the same type. This constraint makes the output of the bart create command more predictable. For example, without arguments, the bart create command catalogs all ZFS file systems under the root (/) directory. However, no NFS or TMPFS file systems or mounted CD-ROMs would be cataloged. When creating a manifest, do not attempt to audit file systems on a network. Note that using BART to monitor networked file systems can consume large resources to generate manifests that will have little value.
For more information about BART manifests, see BART Manifest File Format.
The report tool has three inputs: the two manifests to be compared and an optional user-provided rules file that indicates which discrepancies are to be flagged.
You use the bart compare command to compare two manifests, a control manifest and a test manifest. These manifests must be prepared with the same file systems, options, and rules file that you use with the bart create command.
The output of the bart compare command is a report that lists per-file discrepancies between the two manifests. A discrepancy is a change to any attribute for a given file that is cataloged for both manifests. Additions or deletions of file entries between the two manifests are also considered discrepancies.
There are two levels of control when reporting discrepancies:
When generating a manifest
When producing reports
These levels of control are intentional, since generating a manifest is more costly than reporting discrepancies between two manifests. Once you have created manifests, you have the ability to compare manifests from different perspectives by running the bart compare command with different rules files.
For more information about BART reports, see BART Reporting.
The rules file is a text file that you can optionally use as input to the bart command. This file uses inclusion and exclusion rules. A rules file is used to create custom manifests and reports. A rules file enables you to express in a concise syntax which sets of files you want to catalog, as well as which attributes to monitor for any given set of files. When you compare manifests, the rules file aids in flagging discrepancies between the manifests. Using a rules file is an effective way to gather specific information about files on a system.
You create a rules file by using a text editor. With a rules file, you can perform the following tasks:
Use the bart create command to create a manifest that lists information about all or specific files on a system.
Use the bart compare command to generate a report that monitors specific attributes of a file system.
You can create several rules files for different purposes. However, if you create a manifest by using a rules file, you must use the same rules file when you compare the manifests. If you do not use the same rules file when comparing manifests that were created with a rules file, the output of the bart compare command will list many invalid discrepancies.
A rules file can also contain syntax errors and other ambiguous information as a result of user error. If a rules file does contain misinformation, these errors will also be reported.
Using a rules file to monitor specific files and file attributes on a system requires planning. Before you create a rules file, decide which files and file attributes on the system you want to monitor. Depending on what you are trying to accomplish, you might use a rules file to create manifests, compare manifests, or for purposes.