The situation is simple: I have a Galera Cluster with two nodes.
I create a new database from a .SQL archive (obtained via mysqldump) in one node. The database is quite big: more or less 500 GB. The other node begins the synchronization but it always stops when the database has reached the same size (4 GB aprox.).
Is there any parameter that limits the process? What can be the problem?
Just if it helps anyone: The problem is related to the database engine. In this case, it was MyIsam and Galera Cluster only works with Innodb.
Related
I am having problems trying to build a database solution for the experiment to ensure HA and performance(sharding).
Now, I have a spider node and two galera clusters (3 nodes in each cluster), as shown in the figure below, and this configuration works well in general cases.:
However, as far as I know, when the spider engine performs sharding, it must assign primary IP to distribute SQL statements to two nodes in different Galera clusters.
So my first question here is:
Q1): When the machine .12 shuts down due to destruction, how can I make .13 or .14(one of them) automatically replace .12?
The servers that spider engine know
Q2): Are there any open source tools (or technologies) that can help me deal with this situation? If so, please explain how it works. (Maybe MaxScale? But I never knew what it is and what it can do.)
Q3): The motivation for this experiment is as follows. An automated factory has many machines, and each machine generates some data that must be recorded during the production process (maybe hundreds or thousands of data per second) to observe the operation of the machine and make the quality of each batch of products the best.
So my question is: how about this architecture (Figure 1)? or please provides your suggestions.
You could use MaxScale in front of the Galera cluster to make the individual nodes appear like a combined cluster. This way Spider will be able to seamlessly access the shard even if one of the nodes fails. You can take a look at the MaxScale tutorial for instructions on how to configure it for a Galera cluster.
Something like this should work:
This of course has the same limitation that a single database node has: if the MaxScale server goes down, you'll have to switch to a different MaxScale for that cluster. The benefit of using MaxScale is that it is in some sense stateless which means it can be started and stopped almost instantly. A network load balancer (e.g. ELB) can already provide some form of protection from this problem.
How do i setup multiple mariadb server in one single VM using Galera Cluster?
If configuration links are available please share me?
I have searched in galera website its says add the nodes into cluster and not the adding the multiple mariadb server into cluster
Analysis of having 3 Galera nodes in a single server,
All 3 in a single VM
One in each of 3 VMs
No VMs
Notes:
Galera provides crash protection -- if a node goes down due to hardware failure, the other nodes continue serving the database needs. Not so with all of them sharing the same server and disk(s).
By having multiple instances of MySQL (whether as Galera nodes or not), you can make better use of CPUs. But, since MySQL rarely needs all of the available CPU, I see no advantage in this configuration.
Each instance uses some RAM for static things -- 3 instances leads to 3 copies of such. Other things (eg, caches) scale with RAM size.
No advantage in networking.
(There may be other reasons why there is virtually no difference between a single instance and multiple instances.)
I have a Mariadb Galera cluster with 2 nodes and it is up and running.
Before moving to production, I want to make sure that if a node crashes abruptly, It should come up on its own.
I tried using systemd "restart", but after killing the mysql process the mariadb service does not come up, so, is there any tool or method, that I can use to automate bringing up the nodes after crashes?
Galera clusters needs to have quorum (3 nodes).
In order to avoid a split-brain condition, the minimum recommended number of nodes in a cluster is 3. Blocking state transfer is yet another reason to require a minimum of 3 nodes in order to enjoy service availability in case one of the members fails and needs to be restarted. While two of the members will be engaged in state transfer, the remaining member(s) will be able to keep on serving client requests.
You can read more here.
Currently,I am having mariadb galera cluster operating on two instances of maria db and each node working as Master, replicating data seamlessly. Now, on one node, I want to control one of my database, table etc to not replicate. Can we control the replication behavior to the layer of table, database etc.
By having only 2 nodes on a Galera cluster, you eliminate automatic recovery from a node fault.
By having a db that exists on only one node, you are eliminating the ability to failover by any means.
So, I ask, why use Galera at all?
Back to your question... Galera does not want you to do what you are asking. Maybe there is some letting to let you have MyISAM or MEMORY without replicating it. I don't think you can avoid replicating InnoDB tables.
Now i'm find and config mariadb galera cluster? But i don't know why mariadb galera cluster only support InnoDB.
Pls advice to fix it.
Thanks alots
There is essentially no reason to support any engine other than InnoDB. You can have MyISAM or MEMORY tables, but not get the synchronized replication to the other nodes.
Only with InnoDB, can the synchronous replication be achieved. I feel certain that MyISAM and MEMORY will never be fully supported. However, other transaction-safe engines (Tokudb?) might some day.
Why do you want some other engine? Perhaps we can help you achieve the real goal by some other means.
Addenda...
Synchronous replication, the way Galera implemented, requires being able to ROLLBACK even at COMMIT. Otherwise, duplicate keys would be an unsolvable problem when allowing writes to all nodes.
An aside... NDB takes a radically different approach -- "eventual consistency", wherein duplicate keys can get into the system, but the user has to provide an algorithm for fixing the mess.
InnoDB on a single machine checks as the statements within the transaction are being performed. Galera does not. It is "optimistic" -- transactions are performed without checking the other nodes until the COMMIT. This provided performance because of only a single roundtrip to each other node. (Hence, "medium sized" transactions are optimal.)
MyISAM has no way to do ROLLBACK; it depends on locking table up front. Locking tables on another node would be very clumsy and inefficient.
Galera can work efficiently even in a WAN -- again because of the single action at COMMIT.