Updated URLs for DITA (pingcap#1137)

* Updated URLs for DITA

Author: kolbe

Diff for: dev/how-to/deploy/data-migration-with-ansible.md

@@ -193,7 +193,7 @@ You can choose one of the following two types of cluster topology according to y
 
 - [The cluster topology of multiple DM-worker instances on each node](#option-2-use-the-cluster-topology-of-multiple-dm-worker-instances-on-each-node)
 
-    Generally, it is recommended to deploy one DM-worker instance on each node. However, if the CPU and memory of your machine are much better than the required in [Hardware and Software Requirements](/op-guide/recommendation.md), and you have more than 2 disks in one node or the capacity of one SSD is larger than 2 TB, you can deploy no more than 2 DM-worker instances on a single node.
+    Generally, it is recommended to deploy one DM-worker instance on each node. However, if the CPU and memory of your machine are much better than the required in [Hardware and Software Requirements](/dev/how-to/deploy/hardware-recommendations.md), and you have more than 2 disks in one node or the capacity of one SSD is larger than 2 TB, you can deploy no more than 2 DM-worker instances on a single node.
 
 ### Option 1: Use the cluster topology of a single DM-worker instance on each node
 

Diff for: dev/how-to/deploy/from-tarball/production-environment.md

@@ -202,7 +202,7 @@ Follow the steps below to start PD, TiKV, and TiDB:
 > **Note:**
 >
 > - If you start TiKV or deploy PD in the production environment, it is highly recommended to specify the path for the configuration file using the `--config` parameter. If the parameter is not set, TiKV or PD does not read the configuration file.
-> - To tune TiKV, see [Performance Tuning for TiKV](/op-guide/tune-tikv.md).
-> - If you use `nohup` to start the cluster in the production environment, write the startup commands in a script and then run the script. If not, the `nohup` process might abort because it receives exceptions when the Shell command exits. For more information, see [The TiDB/TiKV/PD process aborts unexpectedly](/trouble-shooting.md#the-tidbtikvpd-process-aborts-unexpectedly).
+> - To tune TiKV, see [Performance Tuning for TiKV](/dev/reference/performance/tune-tikv.md).
+> - If you use `nohup` to start the cluster in the production environment, write the startup commands in a script and then run the script. If not, the `nohup` process might abort because it receives exceptions when the Shell command exits. For more information, see [The TiDB/TiKV/PD process aborts unexpectedly](/dev/how-to/troubleshoot/cluster-setup.md#the-tidbtikvpd-process-aborts-unexpectedly).
 
-For the deployment and use of TiDB monitoring services, see [Monitor a TiDB Cluster](/op-guide/monitor.md).
+For the deployment and use of TiDB monitoring services, see [Monitor a TiDB Cluster](/dev/how-to/monitor/monitor-a-cluster.md).

Diff for: dev/how-to/deploy/orchestrated/ansible.md

@@ -21,10 +21,10 @@ You can use the TiDB-Ansible configuration file to set up the cluster topology a
 - Deploy the whole TiDB cluster
 - [Start the TiDB cluster](/dev/how-to/deploy/orchestrated/ansible-operations.md#start-a-cluster)
 - [Stop the TiDB cluster](/dev/how-to/deploy/orchestrated/ansible-operations.md#stop-a-cluster)
-- [Modify component configuration](/op-guide/ansible-deployment-rolling-update.md#modify-component-configuration)
-- [Scale the TiDB cluster](/op-guide/ansible-deployment-scale.md)
-- [Upgrade the component version](/op-guide/ansible-deployment-rolling-update.md#upgrade-the-component-version)
-- [Enable the cluster binlog](/tools/tidb-binlog-cluster.md)
+- [Modify component configuration](/dev/how-to/maintain/upgrade/rolling-updates-with-ansible.md#modify-component-configuration)
+- [Scale the TiDB cluster](/dev/how-to/maintain/scale/with-ansible.md)
+- [Upgrade the component version](/dev/how-to/upgrade/rolling-updates-with-ansible.md#upgrade-the-component-version)
+- [Enable the cluster binlog](/dev/reference/tools/tidb-binlog/overview.md)
 - [Clean up data of the TiDB cluster](/dev/how-to/deploy/orchestrated/ansible-operations.md#clean-up-cluster-data)
 - [Destroy the TiDB cluster](/dev/how-to/deploy/orchestrated/ansible-operations.md#destroy-a-cluster)
 
@@ -539,7 +539,7 @@ To enable the following control variables, use the capitalized `True`. To disabl
 | cluster_name | the name of a cluster, adjustable |
 | tidb_version | the version of TiDB, configured by default in TiDB-Ansible branches |
 | process_supervision | the supervision way of processes, systemd by default, supervise optional |
-| timezone | the global default time zone configured when a new TiDB cluster bootstrap is initialized; you can edit it later using the global `time_zone` system variable and the session `time_zone` system variable as described in [Time Zone Support](/sql/time-zone.md); the default value is `Asia/Shanghai` and see [the list of time zones](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones) for more optional values |
+| timezone | the global default time zone configured when a new TiDB cluster bootstrap is initialized; you can edit it later using the global `time_zone` system variable and the session `time_zone` system variable as described in [Time Zone Support](/dev/how-to/configure/time-zone.md); the default value is `Asia/Shanghai` and see [the list of time zones](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones) for more optional values |
 | enable_firewalld | to enable the firewall, closed by default; to enable it, add the ports in [network requirements](/dev/how-to/deploy/hardware-recommendations.md#network-requirements) to the white list |
 | enable_ntpd | to monitor the NTP service of the managed node, True by default; do not close it |
 | set_hostname | to edit the hostname of the managed node based on the IP, False by default |

Diff for: dev/how-to/deploy/tispark.md

@@ -7,7 +7,7 @@ aliases: ['/docs/tispark/tispark-quick-start-guide/']
 
 # TiSpark Quick Start Guide
 
-To make it easy to [try TiSpark](/tispark/tispark-user-guide.md), the TiDB cluster installed using TiDB-Ansible integrates Spark, TiSpark jar package and TiSpark sample data by default.
+To make it easy to [try TiSpark](/dev/reference/tispark.md), the TiDB cluster installed using TiDB-Ansible integrates Spark, TiSpark jar package and TiSpark sample data by default.
 
 ## Deployment information
 

Diff for: dev/how-to/get-started/explore-sql.md

@@ -7,7 +7,7 @@ aliases: ['/docs/try-tidb']
 
 # Explore SQL with TiDB
 
-After you successfully deploy a TiDB cluster, you can run SQL statements in TiDB. Because TiDB is compatible with MySQL, you can use THE MySQL client to connect to TiDB and run MySQL statements directly in most of the cases. For more information, see [Compatibility with MySQL](/sql/mysql-compatibility.md).
+After you successfully deploy a TiDB cluster, you can run SQL statements in TiDB. Because TiDB is compatible with MySQL, you can use THE MySQL client to connect to TiDB and run MySQL statements directly in most of the cases. For more information, see [Compatibility with MySQL](/dev/reference/mysql-compatibility.md).
 
 This page includes some basic SQL statements such as CRUD operations. For a complete list of the statements, see [TiDB SQL Syntax Diagram](https://pingcap.github.io/sqlgram/).
 

Diff for: dev/how-to/get-started/local-cluster/install-from-binary.md

@@ -9,7 +9,7 @@ aliases: ['/docs/op-guide/binary-local-deployment/']
 
 This guide provides installation instructions for all TiDB components on a single developer machine. It is intended for evaluation purposes, and does not match the recommended usage for production systems.
 
-See also [testing environment](/op-guide/binary-testing-deployment.md) and [production enviroment](/op-guide/binary-deployment.md) deployment.
+See also [testing environment](/dev/how-to/deploy/from-tarball/testing-environment.md) and [production enviroment](/dev/how-to/deploy/from-tarball/production-environment.md) deployment.
 
 The following local TCP ports will be used:
 
@@ -37,7 +37,7 @@ EOF
 sudo cp /tmp/tidb.conf /etc/security/limits.d/
 sudo sysctl -w fs.file-max=1000000
 ```
-See the [production deployment](/op-guide/binary-deployment.md) optional kernel tuning parameters.
+See the [production deployment](/dev/how-to/deploy/from-tarball/production-environment.md) optional kernel tuning parameters.
 
 ### Create a database running user account
 

Diff for: dev/how-to/get-started/local-cluster/install-from-docker-compose.md

@@ -174,6 +174,6 @@ docker-compose exec tispark-master /opt/spark/bin/pyspark
 docker-compose exec tispark-master /opt/spark/bin/sparkR
 ```
 
-For more details about TiSpark, see [here](/tispark/tispark-quick-start-guide.md).
+For more details about TiSpark, see [here](/dev/how-to/deploy/tispark.md).
 
 Here is [a 5-minute tutorial](https://www.pingcap.com/blog/how_to_spin_up_an_htap_database_in_5_minutes_with_tidb_tispark/) for macOS users that shows how to spin up a standard TiDB cluster using Docker Compose on your local computer.

Diff for: dev/how-to/get-started/read-historical-data.md

@@ -36,7 +36,7 @@ After reading data from history versions, you can read data from the latest vers
 
 TiDB implements Multi-Version Concurrency Control (MVCC) to manage data versions. The history versions of data are kept because each update/removal creates a new version of the data object instead of updating/removing the data object in-place. But not all the versions are kept. If the versions are older than a specific time, they will be removed completely to reduce the storage occupancy and the performance overhead caused by too many history versions.
 
-In TiDB, Garbage Collection (GC) runs periodically to remove the obsolete data versions. For GC details, see [TiDB Garbage Collection (GC)](/op-guide/gc.md)
+In TiDB, Garbage Collection (GC) runs periodically to remove the obsolete data versions. For GC details, see [TiDB Garbage Collection (GC)](/dev/reference/garbage-collection.md)
 
 Pay special attention to the following two variables:
 

Diff for: dev/how-to/maintain/backup-and-restore.md

@@ -39,7 +39,7 @@ cd tidb-enterprise-tools-latest-linux-amd64
 
 ## Full backup and restoration using `mydumper`/`loader`
 
-You can use [`mydumper`](/tools/mydumper.md) to export data from MySQL and [`loader`](/tools/loader.md) to import the data into TiDB.
+You can use [`mydumper`](/dev/reference/tools/mydumper.md) to export data from MySQL and [`loader`](/dev/reference/tools/loader.md) to import the data into TiDB.
 
 > **Important**: You must use the `mydumper` from the Enterprise Tools package, and not the `mydumper` provided by your operating system's package manager. The upstream version of `mydumper` does not yet handle TiDB correctly ([#155](https://github.com/maxbube/mydumper/pull/155)). Using `mysqldump` is also not recommended, as it is much slower for both backup and restoration.
 
@@ -84,7 +84,7 @@ In this command,
 
 ### Restore data into TiDB
 
-To restore data into TiDB, use `loader` to import the previously exported data. See [Loader instructions](/tools/loader.md) for more information.   
+To restore data into TiDB, use `loader` to import the previously exported data. See [Loader instructions](/dev/reference/tools/loader.md) for more information.   
 
 ```bash
 ./bin/loader -h 127.0.0.1 -u root -P 4000 -t 32 -d ./var/test

Diff for: dev/how-to/maintain/identify-slow-queries.md

@@ -55,7 +55,7 @@ select * from t_slim, t_wide where t_slim.c0=t_wide.c0;
 * `Is_internal`: Whether the SQL statement is TiDB internal. `true` indicates that the SQL statement is executed internally in TiDB, such as Analyze, load variables, etc.; `false` indicates the SQL statement is executed by the user.
 * `Digest`: The fingerprint of the SQL statement.
 * `Memory_max`: Indicates the maximum memory space used during the execution period of this SQL statement (the unit is byte).
-* `Num_cop_tasks`: The number of [cop-tasks](/sql/understanding-the-query-execution-plan.md).
+* `Num_cop_tasks`: The number of [cop-tasks](/dev/reference/performance/understanding-the-query-execution-plan.md).
 * `Cop_proc_avg`: The average execution time of cop-tasks.
 * `Cop_proc_p90`: The P90 execution time of cop-tasks.
 * `Cop_proc_max`: The maximum execution time of cop-tasks.

Diff for: dev/how-to/migrate/from-mysql.md

@@ -13,9 +13,9 @@ You can use `mydumper` to export data from MySQL and `loader` to import the data
 
 > **Note:**
 >
-> Although TiDB also supports the official `mysqldump` tool from MySQL for data migration, it is not recommended to use it. Its performance is much lower than `mydumper` / `loader` and it takes much time to migrate large amounts of data. It is important to use the `mydumper` provided by TiDB and not the upstream `mydumper` version.  See [mydumper](/tools/mydumper.md) for more information.
+> Although TiDB also supports the official `mysqldump` tool from MySQL for data migration, it is not recommended to use it. Its performance is much lower than `mydumper` / `loader` and it takes much time to migrate large amounts of data. It is important to use the `mydumper` provided by TiDB and not the upstream `mydumper` version.  See [mydumper](/dev/reference/tools/mydumper.md) for more information.
 
-`Mydumper` and `loader` can be [downloaded as part of Enterprise Tools](/tools/download.md).
+`Mydumper` and `loader` can be [downloaded as part of Enterprise Tools](/dev/reference/tools/download.md).
 
 ### Export data from MySQL
 
@@ -38,7 +38,7 @@ In this command,
 
 ### Import data to TiDB
 
-Use `loader` to import the data from MySQL to TiDB. See [Loader instructions](/tools/loader.md) for more information.
+Use `loader` to import the data from MySQL to TiDB. See [Loader instructions](/dev/reference/tools/loader.md) for more information.
 
 ```bash
 ./bin/loader -h 127.0.0.1 -u root -P 4000 -t 32 -d ./var/test

Diff for: dev/how-to/migrate/incrementally-from-mysql.md

@@ -9,7 +9,7 @@ aliases: ['/docs/op-guide/migration-incremental/']
 
 The [previous guide](/dev/how-to/migrate/from-mysql.md) introduces how to import a full database from MySQL to TiDB using `mydumper`/`loader`. This methodology is not recommended for large databases with frequent updates, since it can lead to a larger downtime window during migration. It is instead recommended to use syncer.
 
-Syncer can be [downloaded as part of Enterprise Tools](/tools/download.md).
+Syncer can be [downloaded as part of Enterprise Tools](/dev/reference/tools/download.md).
 
 Assuming the data from `t1` and `t2` is already imported to TiDB using `mydumper`/`loader`. Now we hope that any updates to these two tables are synchronized to TiDB in real time.
 

Diff for: dev/how-to/migrate/overview.md

@@ -13,11 +13,11 @@ This document describes scenarios for migrating data into TiDB from either MySQL
 
 Migrations will often make use of the following tools. The following is a brief overview of their usage:
 
-- [`mydumper`](/tools/mydumper.md) exports data from MySQL. It is recommended over using mysqldump.
-- [`loader`](/tools/loader.md) imports data in mydumper format into TiDB.
-- [`syncer`](/tools/syncer.md) acts like a MySQL replication slave and pushes data from MySQL into TiDB.
-- [DM](/tools/dm/overview.md) (Data Migration) integrates the functions of mydumper, Loader and syncer to support the export and import of full-size data, as well as incremental synchronization of MySQL Binlog data, and supports data synchronization of a more complete pooled table scenario.
-- [TiDB-Lightning](/tools/lightning/overview-architecture.md) imports data to TiDB in an optimized way. For example, a 1TiB backup could take 24+ hours to import with loader, while it will typically complete at least 3 times faster in TiDB-Lightning.
+- [`mydumper`](/dev/reference/tools/mydumper.md) exports data from MySQL. It is recommended over using mysqldump.
+- [`loader`](/dev/reference/tools/loader.md) imports data in mydumper format into TiDB.
+- [`syncer`](/dev/reference/tools/syncer.md) acts like a MySQL replication slave and pushes data from MySQL into TiDB.
+- [DM](/dev/reference/tools/data-migration/overview.md) (Data Migration) integrates the functions of mydumper, Loader and syncer to support the export and import of full-size data, as well as incremental synchronization of MySQL Binlog data, and supports data synchronization of a more complete pooled table scenario.
+- [TiDB-Lightning](/dev/reference/tools/tidb-lightning/overview.md) imports data to TiDB in an optimized way. For example, a 1TiB backup could take 24+ hours to import with loader, while it will typically complete at least 3 times faster in TiDB-Lightning.
 
 ## Scenarios
 
@@ -54,4 +54,4 @@ To import data from another database, it is recommended to:
 - Export the data as CSV format.
 - Import the data using TiDB-Lightning.
 
-For more information, refer to [CSV support for TiDB-Lightning](/tools/lightning/csv.md).
+For more information, refer to [CSV support for TiDB-Lightning](/dev/reference/tools/tidb-lightning/csv.md).

Diff for: dev/how-to/scale/horizontally.md

@@ -13,11 +13,11 @@ The capacity of a TiDB cluster can be increased or reduced without affecting onl
 
 > **Note:**
 >
-> If your TiDB cluster is deployed using Ansible, see [Scale the TiDB Cluster Using TiDB-Ansible](../op-guide/ansible-deployment-scale.md).
+> If your TiDB cluster is deployed using Ansible, see [Scale the TiDB Cluster Using TiDB-Ansible](/dev/how-to/scale/with-ansible.md).
 
 The following part shows you how to add or delete PD, TiKV or TiDB nodes.
 
-About `pd-ctl` usage, refer to [PD Control User Guide](../tools/pd-control.md).
+About `pd-ctl` usage, refer to [PD Control User Guide](/dev/reference/tools/pd-control.md).
 
 ## PD
 

Diff for: dev/how-to/troubleshoot/cluster-setup.md

@@ -15,7 +15,7 @@ You can use this guide to help you diagnose and solve basic problems while using
 - The configuration and deployment topology
 - The TiDB component related issue in `dmesg`
 
-For other information, see [Frequently Asked Questions (FAQ)](/FAQ.md).
+For other information, see [Frequently Asked Questions (FAQ)](/faq/tidb.md).
 
 ## Cannot connect to the database
 
@@ -39,7 +39,7 @@ For other information, see [Frequently Asked Questions (FAQ)](/FAQ.md).
 See the following for the situations when the `tidb-server` cannot be started:
 
 - Error in the startup parameters.
-    See the [TiDB configuration and options](op-guide/configuration.md#tidb).
+    See the [TiDB configuration and options](/dev/reference/configuration/tidb-server/configuration.md).
 - The port is occupied.
     Use the `lsof -i:port` command to show all the networking related to a given port and make sure the port to start the `tidb-server` is not occupied.
 + Cannot connect to `pd-server`.
@@ -51,7 +51,7 @@ See the following for the situations when the `tidb-server` cannot be started:
 
 See the following for the situations when the `tikv-server` cannot be started:
 
-- Error in the startup parameters: See the [TiKV configuration and options](op-guide/configuration.md#tikv).
+- Error in the startup parameters: See the [TiKV configuration and options](/dev/reference/configuration/tikv-server/configuration.md).
 - The port is occupied: Use the `lsof -i:port` command to show all the networking related to a given port and make sure the port to start the `tikv-server` is not occupied.
 + Cannot connect to `pd-server`.
     - Check if the network between TiDB and PD is running smoothly, including whether the network can be pinged or if there is any issue with the Firewall configuration.
@@ -64,7 +64,7 @@ See the following for the situations when the `tikv-server` cannot be started:
 See the following for the situations when the `pd-server` cannot be started:
 
 - Error in the startup parameters.
-    See the [PD configuration and options](op-guide/configuration.md##placement-driver-pd).
+    See the [PD configuration and options](/dev/reference/configuration/pd-server/configuration.md).
 - The port is occupied.
     Use the `lsof -i:port` command to show all the networking related to a given port and make sure the port to start the `pd-server` is not occupied.
 
@@ -91,7 +91,7 @@ Before starting the process, make sure the result of `ulimit -n` is large enough
 
 ## Database access times out and the system load is too high
 
-First, check the [SLOW-QUERY](/dev/how-to/maintain/identify-slow-queries.md) log and see if it is because of some inappropriate SQL statement.
+First, check the [slow query log](/dev/how-to/maintain/identify-slow-queries.md) and see if it is because of some inappropriate SQL statement.
 If you failed to solve the problem, provide the following information:
 
 + The deployment topology