---
title: Binary log files
---

Several Deephaven processes write [binary log files](../../../data-guide/binary-log-format.md), which contain data that will be written to tables in the [`DbInternal`](../../internal-tables/internal-tables.md) namespace. The locations of these log files are driven by [properties](../../configuration/deephaven-properties-overview.md) similar to the [application log files](./app-log-files.md), including the `logroot` property.

## Binary log locations

When writing a binary log file, the application will determine the location using a three-tiered property search, using the namespace and table name; the most specific result found is used as the location.

```
binaryLogDir.<namespace>.<table name>
binaryLogDir.<namespace>
binaryLogDir
```

If no location is defined for the table or namespace, the location defined by the `binaryLogDir` property will be used.

The default location for binary logs is `/var/log/deephaven/binlogs`. This is defined in Deephaven's [property files](../../configuration/deephaven-properties-overview.md):

```
binaryLogDir=<logroot>/binlogs
```

The default location for binary logs uses the same log root as the application logs (`/var/log/deephaven`), but defines a different subdirectory:

```
binaryLogDir=<logroot>/binlogs
```

[Process Event logs](./db-event-logs.md#process-event-logs) have their own subdirectory:

```
binaryLogDir.DbInternal.ProcessEventLog=<logroot>/binlogs/pel
```

Performance logs have a different subdirectory:

```
binaryLogDir.DbInternal.QueryOperationPerformanceLog=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.QueryPerformanceLog=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.UpdatePerformanceLog=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.QueryOperationPerformanceLogCoreV2=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.QueryPerformanceLogCoreV2=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.UpdatePerformanceLogCoreV2=<logroot>/binlogs/perflogs
binaryLogDir.DbInternal.ServerStateLogCoreV2=<logroot>/binlogs/perflogs
```

## View binary log files with `iriscat` and `iristail`

Because Deephaven log files on disk are in binary format, they can't be viewed as text. Instead use the `iriscat` utility. This can come in handy when there are system errors preventing you from querying the database using the Deephaven Console GUI client.

You can run `iriscat` using this command:

```bash
/usr/illumon/latest/bin/iriscat <path to binary file>
```

For example:

```bash
/usr/illumon/latest/bin/iriscat
/var/log/deephaven/binlogs/test.file.bin.2018-02-02.141436.113-0800
```

This will display the contents of the file in CSV format. To view them in the same file as formatted text, use the `-l` flag. For example:

```bash
/usr/illumon/latest/bin/iriscat -l <path to binary file>
```

You can get the full list of options with `--help`:

```bash
$ /usr/illumon/latest/bin/iriscat --help
usage: IrisCat [-C <columns>] [-d] [-e <endRow>] [-F <format>] [-l] [-s <startRow>] [-S <scale>] [-T <timeZone>]
 -C <columns>    Names of columns to display, comma-separated
 -d              Show debugging information (row flags, column metadata)
 -e <endRow>     Index of the last row displayed
 -F <format>     Format date time columns, comma-separated (e.g. "Column=HH:mm:ss.SSS", or "Column" for ISO8601 microsecond)
 -l              Format output as if it were a log file (useful for ProcessEventLog)
 -s <startRow>   Index of the first row displayed
 -S <scale>      Scale to use when interpreting date time column values (SECOND|MILLI|MICRO|NANO). If not specified, will attempt to infer from value magnitudes.
 -T <timeZone>   Time zone used to interpret and display time columns (e.g. DST or CST)
```

Additionally, the `iristail` command functions similarly, but looks at the end of a binary log, with the additional ability to tail the log file:

```bash
/usr/illumon/latest/bin/iristail -l <path to binary file>
```

You can get the full list of options with `--help`:

```bash
/usr/illumon/latest/bin/iristail --help
usage: IrisTail [-C <columns>] [-d] [-f] [-F <format>] [-l] [-n <number>]
       [-S <scale>] [-T <timeZone>]
 -C <columns>    Names of columns to display, comma-separated
 -d              Show debugging information (row flags, column metadata)
 -f              output appended data as the file grows
 -F <format>     Format date time columns, comma-separated (e.g.
                 "Column=HH:mm:ss.SSS", or "Column" for ISO8601
                 microsecond)
 -l              Format output as if it were a log file (useful for
                 ProcessEventLog)
 -n <number>     number of rows to display
 -S <scale>      Scale to use when interpreting date time column values
                 (SECOND|MILLI|MICRO|NANO). If not specified, will attempt
                 to infer from value magnitudes.
 -T <timeZone>   Time zone used to interpret and display time columns
                 (e.g. DST or CST)
```

## Related documentation

- [Log files overview](./log-files.md)
- [Application log files](./app-log-files.md)
- [Database event logs](./db-event-logs.md)