- Introduction
- Quick Start
- Table Design
- Data Loading
- Overview of data loading
- Load data from a local file system or a streaming data source using HTTP push
- Load data from HDFS or cloud storage
- Routine Load
- Spark Load
- Insert Into
- Change data through loading
- Transform data at loading
- Json Loading
- Synchronize data from MySQL
- Load data by using flink-connector-starrocks
- DataX Writer
- Data Export
- Using StarRocks
- Reference
- SQL Reference
- User Account Management
- Cluster Management
- ADMIN CANCEL REPAIR
- ADMIN CHECK TABLET
- ADMIN REPAIR
- ADMIN SET CONFIG
- ADMIN SET REPLICA STATUS
- ADMIN SHOW CONFIG
- ADMIN SHOW REPLICA DISTRIBUTION
- ADMIN SHOW REPLICA STATUS
- ALTER SYSTEM
- CANCEL DECOMMISSION
- CREATE FILE
- DROP FILE
- INSTALL PLUGIN
- SHOW BACKENDS
- SHOW BROKER
- SHOW FILE
- SHOW FRONTENDS
- SHOW FULL COLUMNS
- SHOW INDEX
- SHOW PLUGINS
- SHOW TABLE STATUS
- UNINSTALL PLUGIN
- DDL
- ALTER DATABASE
- ALTER TABLE
- ALTER VIEW
- BACKUP
- CANCEL BACKUP
- CANCEL RESTORE
- CREATE DATABASE
- CREATE INDEX
- CREATE MATERIALIZED VIEW
- CREATE REPOSITORY
- CREATE RESOURCE
- CREATE TABLE AS SELECT
- CREATE TABLE LIKE
- CREATE TABLE
- CREATE VIEW
- CREATE FUNCTION
- DROP DATABASE
- DROP INDEX
- DROP MATERIALIZED VIEW
- DROP REPOSITORY
- DROP RESOURCE
- DROP TABLE
- DROP VIEW
- DROP FUNCTION
- HLL
- RECOVER
- RESTORE
- SHOW RESOURCES
- SHOW FUNCTION
- TRUNCATE TABLE
- DML
- ALTER ROUTINE LOAD
- BROKER LOAD
- CANCEL LOAD
- DELETE
- EXPORT
- GROUP BY
- INSERT
- PAUSE ROUTINE LOAD
- RESUME ROUTINE LOAD
- ROUTINE LOAD
- SELECT
- SHOW ALTER
- SHOW BACKUP
- SHOW DATA
- SHOW DATABASES
- SHOW DELETE
- SHOW DYNAMIC PARTITION TABLES
- SHOW EXPORT
- SHOW LOAD
- SHOW PARTITIONS
- SHOW PROPERTY
- SHOW REPOSITORIES
- SHOW RESTORE
- SHOW ROUTINE LOAD
- SHOW ROUTINE LOAD TASK
- SHOW SNAPSHOT
- SHOW TABLES
- SHOW TABLET
- SHOW TRANSACTION
- SPARK LOAD
- STOP ROUTINE LOAD
- STREAM LOAD
- Data Types
- Auxiliary Commands
- Function Reference
- Java UDFs
- Window Function
- Date Functions
- convert_tz
- curdate
- current_timestamp
- curtime
- datediff
- date_add
- date_format
- date_sub
- date_trunc
- day
- dayname
- dayofmonth
- dayofweek
- dayofyear
- from_days
- from_unixtime
- hour
- minute
- month
- monthname
- now
- quarter
- second
- str_to_date
- timediff
- timestampadd
- timestampdiff
- to_date
- to_days
- unix_timestamp
- utc_timestamp
- weekofyear
- year
- hours_diff
- minutes_diff
- months_diff
- seconds_diff
- weeks_diff
- years_diff
- Aggregate Functions
- Geographic Functions
- String Functions
- JSON Functions
- Overview of JSON functions and operators
- JSON constructor functions
- JSON query and processing functions
- JSON operators
- Aggregate Functions
- Bitmap Functions
- Array Functions
- cast function
- hash function
- Cryptographic Functions
- Math Functions
- Utility Functions
- System variables
- Error code
- System limits
- SQL Reference
- Administration
- FAQ
- Deploy
- Data Migration
- SQL
- Other FAQs
- Benchmark
- Developers
- Contribute to StarRocks
- Code Style Guides
- Use the debuginfo file for debugging
- Development Environment
- Trace Tools
- Integration
Scale in and out
This topic describes how to scale in and out the node of StarRocks.
Scale FE in and out
StarRocks has two types of FE nodes: Follower and Observer. Followers are involved in election voting and writing. Observers are only used to synchronize logs and extend read performance.
- The number of follower FEs (including leader) must be odd, and it is recommended to deploy 3 of them to form a High Availability (HA) mode.
- When the FE is in high availability deployment (1 leader, 2 followers), it is recommended to add Observer FEs for better read performance. * Typically one FE node can work with 10-20 BE nodes. It is recommended that the total number of FE nodes be less than 10. Three is sufficient in most cases.
Scale FE out
After deploying the FE node and starting the service, run the following command to scale FE out.
alter system add follower "fe_host:edit_log_port";
alter system add observer "fe_host:edit_log_port";Scale FE in
FE scale-in is similar to the scale-out. Run the following command to scale FE in.
alter system drop follower "fe_host:edit_log_port";
alter system drop observer "fe_host:edit_log_port";After the expansion and contraction, you can view the node information by running show proc '/frontends';.
Scale BE in and out
After BE is scaled in or out, StarRocks will automatically perform load-balancing without affecting the overall performance.
Scale BE out
Run the following command to scale BE out.
alter system add backend 'be_host:be_heartbeat_service_port';Run the following command to check the BE status.
show proc '/backends';Scale BE in
There are two ways to scale in a BE node – DROP and DECOMMISSION.
DROP will delete the BE node immediately, and the lost duplicates will be made up by FE scheduling. DECOMMISSION will make sure the duplicates are made up first, and then drop the BE node. DECOMMISSION is a bit more friendly and is recommended for BE scale-in.
The commands of both methods are similar:
alter system decommission backend "be_host:be_heartbeat_service_port";alter system drop backend "be_host:be_heartbeat_service_port";
Drop backend is a dangerous operation, so you need to confirm it twice before executing it
alter system drop backend "be_host:be_heartbeat_service_port";
After the scale-out or scale-in, you can check the status of FE and BE by referring to Cluster Status.