5.4 KiB
| id | title |
|---|---|
| human-readable-byte | Human-readable Byte Configuration Reference |
This page documents configuration properties related to bytes.
These properties can be configured through 2 ways:
- a simple number in bytes
- a number with a unit suffix
A number in bytes
Given that cache size is 3G, there's a configuration as below
# 3G bytes = 3_000_000_000 bytes
druid.cache.sizeInBytes=3000000000
A number with a unit suffix
When you have to put a large number for some configuration as above, it is easy to make a mistake such as extra or missing 0s. Druid supports a better way, a number with a unit suffix.
Given a disk of 1T, the configuration can be
druid.segmentCache.locations=[{"path":"/segment-cache-00","maxSize":"1t"},{"path":"/segment-cache-01","maxSize":"1200g"}]
Note: in above example, both 1t and 1T are acceptable since it's case-insensitive.
Also, only integers are valid as the number part. For example, you can't replace 1200g with 1.2t.
Supported Units
In the world of computer, a unit like K is ambiguous. It means 1000 or 1024 in different contexts, for more information please see Here.
To make it clear, the base of units are defined in Druid as below
| Unit | Description | Base |
|---|---|---|
| K | Kilo Decimal Byte | 1_000 |
| M | Mega Decimal Byte | 1_000_000 |
| G | Giga Decimal Byte | 1_000_000_000 |
| T | Tera Decimal Byte | 1_000_000_000_000 |
| P | Peta Decimal Byte | 1_000_000_000_000_000 |
| KiB | Kilo Binary Byte | 1024 |
| MiB | Mega Binary Byte | 1024 * 1024 |
| GiB | Giga Binary Byte | 1024 * 1024 * 1024 |
| TiB | Tera Binary Byte | 1024 * 1024 * 1024 * 1024 |
| PiB | Peta Binary Byte | 1024 * 1024 * 1024 * 1024 * 1024 |
Unit is case-insensitive. k, kib, KiB, kiB are all acceptable.
Here are two examples
# 1G bytes = 1_000_000_000 bytes
druid.cache.sizeInBytes=1g
# 256MiB bytes = 256 * 1024 * 1024 bytes
druid.cache.sizeInBytes=256MiB
配置文档
本部分内容列出来了每一种Druid服务的所有配置项
推荐的配置文件组织方式
对于Druid的配置文件，一种推荐的结构组织方式为将配置文件放置在Druid根目录的conf目录下，如以下所示：
$ ls -R conf
druid
conf/druid:
_common broker coordinator historical middleManager overlord
conf/druid/_common:
common.runtime.properties log4j2.xml
conf/druid/broker:
jvm.config runtime.properties
conf/druid/coordinator:
jvm.config runtime.properties
conf/druid/historical:
jvm.config runtime.properties
conf/druid/middleManager:
jvm.config runtime.properties
conf/druid/overlord:
jvm.config runtime.properties
每一个目录下都有一个 runtime.properties 文件，该文件中包含了特定的Druid进程相关的配置项，例如 historical
jvm.config 文件包含了每一个服务的JVM参数，例如堆内存属性等
所有进程共享的通用属性位于 _common/common.runtime.properties 中。
通用配置
本节下的属性是应该在集群中的所有Druid服务之间共享的公共配置。
JVM配置最佳实践
在我们的所有进程中有四个需要配置的JVM参数
-Duser.timezone=UTC该参数将JVM的默认时区设置为UTC。我们总是这样设置，不使用其他默认时区进行测试，因此本地时区可能会工作，但它们也可能会发现奇怪和有趣的错误。要在非UTC时区中发出查询，请参阅 查询粒度-Dfile.encoding=UTF-8这类似于时区，我们假设UTF-8进行测试。本地编码可能有效，但也可能导致奇怪和有趣的错误。-Djava.io.tmpdir=<a path>系统中与文件系统交互的各个部分都是通过临时文件完成的，这些文件可能会变得有些大。许多生产系统都被设置为具有小的（但是很快的）/tmp目录，这对于Druid来说可能是个问题，因此我们建议将JVM的tmp目录指向一些有更多内容的目录。此目录不应为volatile tmpfs。这个目录还应该具有良好的读写速度，因此应该强烈避免NFS挂载。-Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager这允许log4j2处理使用标准java日志的非log4j2组件（如jetty）的日志。