conf: document 'storage' properties

Signed-off-by: Eduardo Silva <[email protected]>

conf/fluent-bit.conf

@@ -1,13 +1,13 @@
 [SERVICE]
     # Flush
     # =====
-    # Set an interval of seconds before to flush records to a destination
-    Flush        5
+    # set an interval of seconds before to flush records to a destination
+    flush        5
 
     # Daemon
     # ======
-    # Instruct Fluent Bit to run in foreground or background mode.
-    Daemon       Off
+    # instruct Fluent Bit to run in foreground or background mode.
+    daemon       Off
 
     # Log_Level
     # =========
@@ -19,30 +19,75 @@
     # - debug
     # - trace
     #
-    # By default 'info' is set, that means it includes 'error' and 'warning'.
-    Log_Level    info
+    # by default 'info' is set, that means it includes 'error' and 'warning'.
+    log_level    info
 
-    # Parsers_File
+    # Parsers File
     # ============
-    # Specify an optional 'Parsers' configuration file
-    Parsers_File parsers.conf
-    Plugins_File plugins.conf
+    # specify an optional 'Parsers' configuration file
+    parsers_file parsers.conf
+
+    # Plugins File
+    # ============
+    # specify an optional 'Plugins' configuration file to load external plugins.
+    plugins_file plugins.conf
 
     # HTTP Server
     # ===========
     # Enable/Disable the built-in HTTP Server for metrics
-    HTTP_Server  Off
-    HTTP_Listen  0.0.0.0
-    HTTP_Port    2020
+    http_server  Off
+    http_listen  0.0.0.0
+    http_port    2020
+
+    # Storage
+    # =======
+    # Fluent Bit can use memory and filesystem buffering based mechanisms
+    #
+    # - https://docs.fluentbit.io/manual/administration/buffering-and-storage
+    #
+    # storage metrics
+    # ---------------
+    # publish storage pipeline metrics in '/api/v1/storage'. The metrics are
+    # exported only if the 'http_server' optoin is enabled.
+    #
+    storage.metrics on
+
+    # storage.path
+    # ------------
+    # absolute file system path to store filesystem data buffers (chunks).
+    #
+    # storage.path /tmp/storage
+
+    # storage.sync
+    # ------------
+    # configure the synchronization mode used to store the data into the
+    # filesystem. It can take the values normal or full.
+    #
+    # storage.sync normal
+
+    # storage.checksum
+    # ----------------
+    # enable the data integrity check when writing and reading data from the
+    # filesystem. The storage layer uses the CRC32 algorithm.
+    #
+    # storage.checksum off
+
+    # storage.backlog.mem_limit
+    # -------------------------
+    # if storage.path is set, Fluent Bit will look for data chunks that were
+    # not delivered and are still in the storage layer, these are called
+    # backlog data. This option configure a hint of maximum value of memory
+    # to use when processing these records.
+    #
+    # storage.backlog.mem_limit 5M
 
 [INPUT]
-    Name cpu
-    Tag  cpu.local
-    # Interval Sec
-    # ====
+    name cpu
+    tag  cpu.local
+
     # Read interval (sec) Default: 1
-    Interval_Sec 1
+    interval_sec 1
 
 [OUTPUT]
-    Name  stdout
-    Match *
+    name  stdout
+    match *