# Output Files

### Raw Data

All raw data is recorded in a single compressed file with the extension raw.gz if the perl compression library has been installed. If that library is not there it will be written to a non-compressed file with the extension raw. The only exception to this rule is the process raw file which can be useful on systems with a large number of processes (see the description of --tworaw) and which has the extension rawp.

### Plot Data

There are actually 2 main types of plot data - summary and detail. Summary plot data, for those subsystems selected with lower case letters, is always stored in a single file, one line per time period, with the extension tab. The primary reason for this is that the data for each subsystem is of a fixed length and there is really no benefit in separating it into multiple files.

Detail plot data, which is typically for devices for which there can be multiple instances such as CPUs, is recorded in one file per detail type with an extension that reflects the type of data stored in that file. Each line contains instance data of a fixed number of fields for that particular device. Although TCP do not have instance data, it does have a detail component and is also written to its own detail file. Process and Slab data are also treated like detail data because they too require multiple lines per monitoring period.

### Exception Data

Exception data is written to a file in the same format as detail data with an X appended to its name. Since exception data is not of a known format across the entire device as is detail data, it cannot be written as a single line, but rather is written as one line per device. Each line is prefaced with a date/time stamp and the number of the device (0 based).

### Collectl Messages

Periodically collectl logs various types of messages to its own message log to avoid situations in which an unexpected situation or a collectl bug might causes the flooding of /var/log/mesasages. However, the more serious messages are written to both as described here.

updated Feb 21, 2011