cleanup op-guide (pingcap#1140)

Author: morgo

TOC.md

@@ -196,6 +196,7 @@
       - [MySQL System Variables](dev/reference/configuration/tidb-server/mysql-variables.md)
       - [TiDB Specific System Variables](dev/reference/configuration/tidb-server/tidb-specific-variables.md)
       - [Configuration Flags](dev/reference/configuration/tidb-server/configuration.md)
+      - [Configuration File](dev/reference/configuration/tidb-server/configuration-file.md)
     + pd-server
       - [Configuration Flags](dev/reference/configuration/pd-server/configuration.md)
     + tikv-server

dev/how-to/upgrade/from-previous-version.md

@@ -2,7 +2,7 @@
 title: TiDB 2.1 Upgrade Guide
 summary: Learn how to upgrade from TiDB 2.0 (TiDB 2.0.1 or later) or TiDB 2.1 RC version to TiDB 2.1 GA version.
 category: how-to
-aliases: ['/docs/op-guide/tidb-v2.1-upgrade-guide/','/docs/dev/how-to/maintain/upgrade/from-previous-version/']
+aliases: ['/docs/op-guide/tidb-v2.1-upgrade-guide/','/docs/dev/how-to/maintain/upgrade/from-previous-version/','/docs/op-guide/tidb-v2.0-upgrade-guide/']
 ---
 
 # TiDB 2.1 Upgrade Guide

dev/reference/configuration/pd-server/configuration.md

@@ -2,7 +2,7 @@
 title: PD Configuration Flags
 summary: Learn some configuration flags of PD.
 category: reference
-aliases: ['/docs/op-guide/pd-configuration/']
+aliases: ['/docs/op-guide/pd-configuration/','/docs/op-guide/pd-api-v1/']
 ---
 
 # PD Configuration Flags

op-guide/tidb-config-file.md renamed to dev/reference/configuration/tidb-server/configuration-file.md

@@ -2,13 +2,14 @@
 title: TiDB Configuration File Description
 summary: Learn the TiDB configuration file options that are not involved in command line options.
 category: deployment
+aliases: ['/docs/op-guide/tidb-config-file/']
 ---
 
 # TiDB Configuration File Description
 
 The TiDB configuration file supports more options than command line options. You can find the default configuration file in [config/config.toml.example](https://github.com/pingcap/tidb/blob/master/config/config.toml.example) and rename it to `config.toml`.
 
-This document describes the options that are not involved in command line options. For command line options, see [here](../op-guide/configuration.md).
+This document describes the options that are not involved in command line options. For command line options, see [here](/dev/reference/configuration/tidb-server/configuration.md).
 
 ### `split-table`
 
@@ -229,4 +230,4 @@ Configuration about the transaction latch. It is recommended to enable it when m
 ### `capacity`
 
 - The number of slots corresponding to Hash, which automatically adjusts upward to an exponential multiple of 2. Each slot occupies 32 Bytes of memory. If set too small, it might result in slower running speed and poor performance in the scenario where data writing covers a relatively large range (such as importing data).
-- Default: 1024000
+- Default: 1024000