Cloud Storage FUSE configuration file

This page describes how to use a Cloud Storage FUSE configuration file to configure the behavior of Cloud Storage FUSE in a persistent manner. To use the configuration file, specify the path to the configuration file in the --config-file flag as part of your mount command.

The configuration file is a YAML file that uses the following format and fields. Some of the fields can also be specified by using command-line options.

write:
  create-empty-file: boolean
logging:
  file-path: "string"
  format: enum
  severity: enum
  log-rotate:
    max-file-size-mb: integer
    backup-file-count: integer
    compress: boolean
file-cache:
  max-size-mb: integer
  cache-file-for-range-read: boolean
metadata-cache:
  stat-cache-max-size-mb: integer
  ttl-secs:integer
  type-cache-max-size-mb: integer
cache-dir: integer

Configuration fields

The following table describes the fields you can specify in your configuration file. Unless stated otherwise, all fields are optional.

Field	Description
create-empty-file	A Boolean value that specifies whether or not to create a zero-byte file in Cloud Storage when you start writing to a new file in the mounted bucket. If this field is unspecified, the value defaults to false.
file-path	The path to the log file where logs will be written, specified as a string. For example, /var/log. If this field is unspecified, the logs are routed to stdout when Cloud Storage FUSE runs in foreground mode and to syslogs when Cloud Storage FUSE runs in background mode.
format	The format in which logs are generated, expressed as an enum. Values are text or json. If this field is unspecified, the value defaults to json.
severity	The severity of logs you want Cloud Storage FUSE to generate, expressed as an enum. The severity levels are ordered from lowest severity to highest severity: trace debug info warning error When you specify a severity level, Cloud Storage FUSE generates logs having equal or higher severity. For example, when you specify warning, Cloud Storage FUSE generates logs for warnings and errors. You can also specify off to turn off all logging. If any of the following three options are also specified as part of your command, the severity level is automatically set to trace: --debug_fuse --debug_gcs --debug_mutex If this field is unspecified, the value defaults to info.
max-file-size-mb	The maximum size in megabytes (MB) that log files can reach before being rotated. The minimum value is 1. If this field is unspecified, the value defaults to 512.
backup-file-count	The maximum number of rotated log files to retain, excluding the active file to which logs are written. When the value is set to 0, all rotated log files are retained. If this field is unspecified, the value defaults to 10.
compress	A Boolean value that specifies whether rotated log files are compressed using gzip. If this field is unspecified, the value defaults to true.
max-size-mb	The maximum size in MiB that the file cache can use. If present, max-size-mb enables file caching in Cloud Storage FUSE and is useful if you want to limit the total capacity the Cloud Storage FUSE cache can use within its mounted directory. Specify -1 to use the cache's entire available capacity in the directory you specify for cache-dir. Specify 0 to disable the file cache. If this field is unspecified, the value defaults to -1.
cache-file-for-range-read	A Boolean value that determines whether the full object should be downloaded asynchronously and stored in the Cloud Storage FUSE cache directory when the first read is done from a non-zero offset. This should be set to true if you plan on performing several random reads or partial reads. If this field is unspecified, the value defaults to false. Note that if you do a partial read starting at offset 0, Cloud Storage FUSE always asynchronously downloads and caches the full object.
stat-cache-max-size-mb	The maximum size in MiB that the stat cache can use. The stat cache is always entirely kept in memory. Specify 32 if your workload involves up to 20,000 files. If your workload is larger than 20,000 files, increase the size by values of 10 for every additional 6,000 files, an average of ~1,500 bytes per file. Specify -1 to let the stat cache use as much memory as needed. Specify 0 to disable the stat cache. If this field is unspecified, the value defaults to 32.
ttl-secs	Defines the time to live (TTL) of cached metadata entries, expressed in seconds. Specify -1 to bypass a TTL expiration and serve the file from the cache whenever it's available. Specify 0 to ensure that the most up to date file is read. Using this value issues a Get metadata call to make sure that the object generation for the file in the cache matches what's stored in Cloud Storage. To learn more, see About the ttl-secs flag. If this field is unspecified, the value defaults to 60.
type-cache-max-size-mb	The maximum size in MiB per directory that the type cache can use. The type cache is always entirely kept in memory. Specify 4 if the maximum number of files within a single directory from the bucket you're mounting contains 20,000 files or less. If the maximum number of files within a single directory that you're mounting contains more than 20,000 files, increase the value by 1 for every 5,000 files, an average of ~200 bytes per file. Specify -1 to let the type cache use as much memory as needed. Specify 0 to disable the type cache. If this field is unspecified, the value defaults to 4.
cache-dir	Specifies the directory for storing file cache data. This field must be specified in order to enable file caching.