oriana19993926782 opened a new issue, #631:
URL: https://github.com/apache/rocketmq-site/issues/631
**What is the purpose of the change**
The current Quick Start documentation is succinct and provides a smooth
onboarding experience for new users. However, during my setup process, I
encountered a few non-trivial issues that required additional steps to resolve.
These issues are likely common among new users and could significantly impact
their initial experience with RocketMQ. I propose adding a "Some Tips" section
to the Quick Start guide to address these potential stumbling blocks.
**Detailed description of the issues and proposed additions**
**1. About slf4j**
While following step 5 of the Quick Start guide to create and run a program
for sending normal messages, I encountered an error:
`Could not find artifact org.slf4j:slf4j-api:jar:27.0.0-SNAPSHOT`
This suggests that Maven could not find the specified dependency version in
its configured repositories, particularly for versions marked as SNAPSHOT,
which are generally unstable and subject to frequent changes. A simpler
solution is to try an earlier stable release version.
Additionally, using the slf4j-api version 2.0.x might lead to the following
error:
`SLF4J: No SLF4J providers were found. SLF4J: Defaulting to no-operation
(NOP) logger implementation`
This indicates that SLF4J did not find any logging implementation in the
project. Since version 2.0.x, SLF4J is only a logging facade, not an
implementation. The solution is to add a logging implementation to the pom.xml,
such as slf4j-nop.jar, slf4j-simple.jar, slf4j-reload4j.jar, slf4j-jdk14.jar,
or logback-classic.jar. Here is an example:
```
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>2.0.3</version>
</dependency>
```
**2. InternalErrorException：The broker's disk is full**
When trying to send messages, clients might encounter the
`InternalErrorException: service not available now. It may be caused by one of
the following reasons: the broker's disk is full`. This can be confusing as
there might still be several GBs of space available on the disk. The term
"full" here refers to a high space utilization rate, not an absolute lack of
space.
For MAC OS systems, running df -h in the terminal to check the disk
partition usage could reveal that the `/System/Volumes/Data `partition has a
high utilization rate, which RocketMQ might be using, almost filled to
capacity. The solution is to free up space in this partition until the
utilization rate drops to a reasonable level.
**3. java.lang.RuntimeException: Lock failed, MQ already started**
After executing step 3 (Start Broker + Proxy) in the document, if you
encounter some challenging issues, be sure to run step 6 (Shut Down the Server)
to safely close the nameserver and broker.
If you directly close the terminal and forcefully exit, the next time you
try to start the Broker + Proxy, you'll find the `Lock failed, MQ already
started error` in the broker's log. This usually means that a RocketMQ Broker
instance is already running, or the previous instance abnormally terminated
without properly releasing the lock file.
To resolve this, you need to:
1. Run `ps aux | grep mqbroker` to check if another Broker instance is
indeed running. If you find any mqbroker processes other than the current grep
command, you can terminate them with the `kill` command.
2. Locate and delete the lock file. The lock file is located in the RocketMQ
runtime data storage (Store) directory, which is usually specified in the
broker's configuration file (i.e., broker.conf) through the storePathRootDir
parameter. If not specified, RocketMQ uses a default storage path depending on
its installation and operating environment:
```
Linux / macOS: ~/store or /home/{username}/store.
Windows: C:\Users\{username}\store.
```
For MacOS, you can directly run the following command in the terminal to
find the lock file:
`find ~/store -name "lock" 2>/dev/null`
**Importance of this issue**
This documentation enhancement is a must-have for new users to avoid common
pitfalls and improve their initial experience with RocketMQ. Currently, the
workaround has been to search for solutions online, which can be time-consuming
and may not always lead to accurate information.
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