Percona MySQL cluster suitable for Cyclos?

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Percona MySQL cluster suitable for Cyclos?

Post by cycloshost » Tue Apr 24, 2012 10:50 pm

Hi, we were reading the Wiki regarding MySQL clustering and seems there are not many options for synchronus replication.

We found Percona clustering, based on Galera and on beta stage. Supports multi-master replication, however it has some limitations, the main being that replication works only with the InnoDB storage engine and unsupported queries like LOCK/UNLOCK TABLES.
Are these limitations compatible with Cyclos?
http://www.percona.com/doc/percona-xtra ... ation.html
Here is a tutorial how to set up three nodes:
http://www.how2centos.com/install-perco ... entos-6-2/

It seems a good option, but we would like to know your opinion.

Thanks!
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admin
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Re: Percona MySQL cluster suitable for Cyclos?

Post by admin » Wed Apr 25, 2012 9:24 am

Hi,

Cyclos should be compatible. The only limitation (last one on the list) is that we do use DLL.
However, we only use DDL for upgrading the database when there is a new version. Database wise there should not be a problem when you shut down the db cluster when you upgrade to a new version (that has db changes).

So in theory it should work. We once tested with Galera but had some problems with it. Sometimes the replication failed. Also the limitation of 3 nodes gave some problems. When one node failed the cluster stopped. We were using the 0,8 version which was not stable yet. So these issues might be solved. There seem to be quite some improvements since version 0,8.

We experienced that performance wise 4 tomcat nodes with 1 mysql server gave the best results. In order to get the best performance you need to make sure you have enough Tomcat nodes.

We posted some test results on the wiki. You can find them here: http://project.cyclos.org/wiki/index.ph ... ce_testing (see results links to pdf files)

Any doubts / questions just let us know.

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Re: Percona MySQL cluster suitable for Cyclos?

Post by cycloshost » Thu Apr 26, 2012 6:54 am

OK, thanks! Then when using Percona if we upgrade to another version of Cyclos we should shut down before all mysql instances of the cluster (only if the new version has database changes).

We are following the instructions of the Performance testing page but... how do we download the cyclos_testbed project? Is it coming with the cyclos 3.6.1 basic installation package? We do not find it.
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Re: Percona MySQL cluster suitable for Cyclos?

Post by admin » Thu Apr 26, 2012 10:38 am

Due to some issues with testbed we had to postpone the release.
We will publish it tomorrow afternoon (Friday)

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Re: Percona MySQL cluster suitable for Cyclos?

Post by admin » Fri Apr 27, 2012 10:05 am

We have been reviewing the testbed and there is still quite some documentation and testing to be done.
It will take about 10 days. After this we will publish.
There is already some on line documentation. (performance and functional testing on the wiki)

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Re: Percona MySQL cluster suitable for Cyclos?

Post by cycloshost » Fri Apr 27, 2012 12:22 pm

Thank you very much, we will make other tests in the meantime before the release.
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Re: Percona MySQL cluster suitable for Cyclos?

Post by admin » Fri May 04, 2012 4:45 pm


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Re: Percona MySQL cluster suitable for Cyclos?

Post by cycloshost » Sat May 12, 2012 4:07 am

Thanks a lot, we will try to make that test next week.

Finally was not possible for us to use Percona but Galera seemed to work fine. We have configured 2 galera databases and 2 arbitrators with a virtual IP using HAProxy.
http://codership.com/products/mysql_galera

How could we make a thoroughly test on the database?
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Re: Percona MySQL cluster suitable for Cyclos?

Post by admin » Mon May 14, 2012 9:36 am

Hello,

We did not manage to have Galera working. But the version we tested did not support arbitrators yet. (we used version 0.8)
This meant there was a minimum of 3 nodes. The cluster did initiate correctly but it froze when putting high load on it.

It seems Galera has quite some improvements since we tried. We will give Galera one more try (version 2.0) and post our findings in this thread.

About the testing.
The first thing to test would be to set it up and disconnect a node and put it back again, and see if it all resumes correctly.
The next step would be to do the same test under high load. You can use the Jmeter project for this. (did you have a look at the test tools yet?)

Lets keep in touch

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Re: Percona MySQL cluster suitable for Cyclos?

Post by luis » Tue May 15, 2012 3:33 pm

We found out that Galera is way more stable than it was when we tested, and could be used.
The problem is that with Galera, the application must be able to retry the transaction in case of deadlocks, and that is something Cyclos currently cannot do.
Right now, it is possible to use Cyclos with Galera, but application errors may pop up occasionally.
However, we're currently working to implement this transaction retry, so every transaction should be safe.
We expect to release this feature on the next version (3.6.2).
Luis Fernando Planella Gonzalez
Cyclos development team

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Re: Percona MySQL cluster suitable for Cyclos?

Post by avf » Wed Dec 10, 2014 7:09 am

Does cyclos 3.7 have transaction retry?

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Re: Percona MySQL cluster suitable for Cyclos?

Post by luis » Wed Dec 10, 2014 7:30 am

avf wrote:Does cyclos 3.7 have transaction retry?
Only when explicitly locking an account before a payment, when the locking fails.
But in general, no.
Luis Fernando Planella Gonzalez
Cyclos development team

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