Remove wrong description about path of file buffer plugin

Although it seems based on v0.12, it's not applicable for v0.14 or
later. We should rewrite it.

Signed-off-by: Takuro Ashie <[email protected]>

Author: ashie

buffer/file.md

@@ -9,49 +9,11 @@ The `file` buffer plugin provides a persistent buffer implementation. It uses fi
 
 ### `path`
 
-| type | required | default | version |
-| :--- | :---: | :--- | :--- |
-| string | ✔ |  | 0.9.0 |
-
-The path where buffer chunks are stored. The '\*' is replaced with random characters. This parameter is required.
-
-This parameter must be unique to avoid the race condition problem. For example, you cannot use a fixed path parameter in `fluent-plugin-forest`. `${tag}` or similar placeholder is needed. Of course, this parameter must also be unique between fluentd instances.
-
-In addition, `path` should not be another `path` prefix. For example, the following configuration does not work well. `/var/log/fluent/foo` resumes `/var/log/fluent/foo.bar`'s buffer files during start phase and it causes `No such file or directory` in `/var/log/fluent/foo.bar` side.
-
-```text
-<match pattern1>
-  <buffer>
-    @type file
-    path /var/log/fluent/foo
-  </buffer>
-</match>
-
-<match pattern2>
-  <buffer>
-    @type file
-    path /var/log/fluent/foo.bar
-  </buffer>
-</match>
-```
-
-Here is the correct version to avoid the prefix problem:
+| type | default | version |
+| :--- | :--- | :--- |
+| string | nil | TBD |
 
-```text
-<match pattern1>
-  <buffer>
-    @type file
-    path /var/log/fluent/foo.baz
-  </buffer>
-</match>
-
-<match pattern2>
-  <buffer>
-    @type file
-    path /var/log/fluent/foo.bar
-  </buffer>
-</match>
-```
+The path where buffer chunks are stored.
 
 Please make sure that you have **enough space in the path directory**. Running out of disk space is a problem frequently reported by users.
 
@@ -88,10 +50,6 @@ This parameter is useful when `.log` is not fit for your environment. See also [
 
 ## Tips
 
-### Multi-Process Environment
-
-If you use this plugin under the multi-process environment, you need to use `@id`/`root_dir` parameters instead of fixed `path` parameter. See [Multi Process Workers](../deployment/multi-process-workers.md#root_dir-id-parameter) article.
-
 ## Limitation
 
 Caution: `file` buffer implementation depends on the characteristics of the local file system. Don't use `file` buffer on remote file systems e.g. NFS, GlusterFS, HDFS, etc. We observed major data loss by using the remote file system.

deployment/multi-process-workers.md

@@ -131,45 +131,6 @@ As of Fluentd v1.4.0, `<worker N-M>` syntax has been introduced:
 
 With this directive, you can specify multiple workers per worker directive.
 
-### `root_dir/@id` parameter
-
-These parameters must be specified when you use the file buffer.
-
-With multi-process workers, you cannot use the fixed `path` configuration for file buffer because it conflicts buffer file path between processes.
-
-```text
-<system>
-  workers 2
-</system>
-
-<match pattern>
-  @type forward
-  <buffer>
-    @type file
-    path /var/log/fluentd/forward # This is not allowed
-  </buffer>
-</match>
-```
-
-Instead of a fixed configuration, fluentd provides the dynamic buffer path based on `root_dir` and `@id` parameters. The stored path is `${root_dir}/worker${worker index}/${plugin @id}/buffer` directory.
-
-```text
-<system>
-  workers 2
-  root_dir /var/log/fluentd
-</system>
-
-<match pattern>
-  @type forward
-  @id out_fwd
-  <buffer>
-    @type file
-  </buffer>
-</match>
-```
-
-With this configuration, `forward` output buffer files are stored into `/var/log/fluentd/worker0/out_fwd/buffer` and `/var/log/fluentd/worker1/out_fwd/buffer` directories.
-
 ## Operation
 
 Each worker consumes memory and disk space separately. Take care while configuring buffer spaces and monitoring memory/disk consumption.