Can you please provide the link where you saw KahaDB replication discussed? I suspect that the content is very out of date since I'm not aware of any current development effort to implement replicated KahaDB.
To the best of my knowledge, the out-of-the-box data store options available to you are KahaDB on NFS and JDBC (with a number of database engines supported). You can also use pluggable storage lockers[1] to decouple the locking technology from the storage technology if necessary (e.g. for NFSv3 whose locks are not supported). In the KahaDB on NFS case, your statement that the data is unavailable when a broker fails is inaccurate. Because the data is written to an NFS share, it is readable by many machines, and as soon as a new broker can acquire the lock due to the active broker's failure, the machine that acquires the lock will become the active broker, read the data file, and begin receiving and delivering messages from/to clients. So I think your assessment that replicated LevelDB is necessary to get resilience without having to use a SQL database wasn't accurate and led you down the wrong path. You should use KahaDB on NFSv4. 1. https://activemq.apache.org/pluggable-storage-lockers Tim On Wed, Jul 7, 2021, 12:13 AM ヤ艾枫o.-- <1169114...@qq.com.invalid> wrote: > 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 > > > ------------------ 原始邮件 ------------------ > 发件人: > "users" > < > tb...@alumni.duke.edu>; > 发送时间: 2021年7月5日(星期一) 晚上7:40 > 收件人: "ActiveMQ Users"<users@activemq.apache.org>; > > 主题: 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 ヤ艾枫o.-- <1169114...@qq.com.invalid> > wrote: > > > I know the levedb was removed. > > but now I use zookeeper + ActiveMQ to build master-slave mode。 > > > > > > > > > > ------------------&nbsp;原始邮件&nbsp;------------------ > > 发件人: > > > "users" > > > < > > jbert...@apache.org&gt;; > > 发送时间:&nbsp;2021年7月5日(星期一) 中午11:22 > > 收件人:&nbsp;"users"<users@activemq.apache.org&gt;; > > > > 主题:&nbsp;Re: I have a question about levedb > > > > > > > > Support for LevelDB was revoked in ActiveMQ 5.14.2, although the store > > implementation was still present in the code-base. The store > implementation > > was removed in 5.17.0. > > > > > > Justin > > > > On Sun, Jul 4, 2021 at 9:48 PM ヤ艾枫o.-- <1169114...@qq.com.invalid > &gt; > > wrote: > > > > &gt; Hi&amp;nbsp; > > &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 > > > <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 > > < > 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> > ;; > > what is means "members"？ > > &gt; Refers to the number of brokers started in the current > cluster, or the > > &gt; number of brokers registered in the zookeeper service
