I learned from the official website that the master-slave modes currently 
supported are "shared file system master slave" and "JDBC master slave".


"Shared file system master slave": the mode depends on shared files and only 
exists on one node. If the host of the node is down, the master-slave mode will 
be invalid


"JDBC": the mode needs to rely on the database, which costs a lot. At the same 
time, the database needs to have the master / slave mode, so that the cluster 
can be robust.


So I had to use activemq+zookeeeper to avoid shared file storage and JDBC 
database storage

We learned from the official website that masterslave > kahadb replication 
(experimental) is in the experimental stage. Is this mode similar to the 
previous ActiveMQ + zookeeper + leveldb and independent of shared files?At the 
same time, when can we go online to provide services


------------------ ???????? ------------------
??????:                                                                         
                                               "users"                          
                                                          
<tb...@alumni.duke.edu&gt;;
????????:&nbsp;2021??7??5??(??????) ????7:40
??????:&nbsp;"ActiveMQ Users"<users@activemq.apache.org&gt;;

????:&nbsp;Re: I have a question about levedb



Let me strengthen the statement made by Justin.

The decision to deprecate and soon remove LevelDB was made because there
was no developer willing/able to maintain the code and no member of the
mailing list willing/able to answer questions, even basic ones, on this
mailing list.

If you aren't prepared to answer your own questions by reading the source
code without any support from this mailing list, and to debug and fix any
bugs you encounter in the Scala code, don't use LevelDB.

And even if you're willing to do those things, you'll be unable to upgrade
ActiveMQ to 5.17.0 or later, even if there are security vulnerabilities or
other compelling reasons to upgrade. I strongly encourage you to switch to
KahaDB immediately.

Tim

On Sun, Jul 4, 2021, 11:45 PM ??????o.-- <1169114...@qq.com.invalid&gt; wrote:

&gt; I know the levedb was removed.
&gt; but now I use zookeeper + ActiveMQ to build master-slave mode??
&gt;
&gt;
&gt;
&gt;
&gt; ------------------&amp;nbsp;????????&amp;nbsp;------------------
&gt; ??????:
&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 "users"
&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 <
&gt; jbert...@apache.org&amp;gt;;
&gt; ????????:&amp;nbsp;2021??7??5??(??????) ????11:22
&gt; ??????:&amp;nbsp;"users"<users@activemq.apache.org&amp;gt;;
&gt;
&gt; ????:&amp;nbsp;Re: I have a question about levedb
&gt;
&gt;
&gt;
&gt; Support for LevelDB was revoked in ActiveMQ 5.14.2, although the store
&gt; implementation was still present in the code-base. The store implementation
&gt; was removed in 5.17.0.
&gt;
&gt;
&gt; Justin
&gt;
&gt; On Sun, Jul 4, 2021 at 9:48 PM ??????o.-- 
<1169114...@qq.com.invalid&amp;gt;
&gt; wrote:
&gt;
&gt; &amp;gt; Hi&amp;amp;nbsp;
&gt; &amp;gt;
&gt; &amp;gt;
&gt; 
https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120
&gt; &amp;gt
&gt; 
<https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120&amp;gt&gt;;
&gt; what is means "members"??
&gt; &amp;gt; Refers to the number of brokers started in the current cluster, 
or the
&gt; &amp;gt; number of brokers registered in the zookeeper service

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