September 23, 2021 @ 12:00 am, by raindog308
In a previous tutorial, we showed you how to setup Galera replication for MariaDB so you could have multi-node, multi-master clusters. We also saw how MariaDB painlessly replicates data. In this tutorial, we’re doing to forcibly interject a little pain into the process by seeing how Galera deals with down loads and replaced nodes.
Once again, we’re using the following cluster setup:
In this design, I’m using the following cluster and anonymized IPs:
- db1.lowend.party on 1.1.1.1
- db2.lowend.party on 2.2.2.2
- db3.lowend.party on 3.3.3.3
Bigger Data
Let’s start by making some bigger data. We’re still using our Buffy the Vampire Slayer-themed table created in the previous tutorial, but if you didn’t follow that one, you can set it up easily:
root@dbsecure:~# mysql Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 47 Server version: 10.3.22-MariaDB-0+deb10u1 Debian 10 Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> create database gtest; Query OK, 1 row affected (0.000 sec) MariaDB [(none)]> use gtest; Database changed MariaDB [gtest]> create table buffy ( name varchar(30), team_role varchar(100) ); Query OK, 0 rows affected (0.012 sec) MariaDB [gtest]>
Now I’d like to load a bigger quantity of data. Start by shutting down db2 and db3. I’m doing this because we’re in synchronous mode and the initial data load will be much faster. On db2 and db3:
systemctl stop mariadbOn db1, I’m going to load 250,000 rows. Here’s the perl script I used to generate the random data. Place this in /root/make_load.pl:
#!/usr/bin/perl -w @lets = qw ( a b c d e f g h i j k l m n o p q r s t u v w x y z ); sub random_word { my $word = ""; for ( my $i = 1; $i<=30; $i++ ) { $c = int(rand($#lets)); $word .= $lets[$c]; } return $word; } open (OUT,">load.sql"); print OUT "use gtest;\n"; for ( $i = 1; $i <=250000; $i++ ) { $name = random_word(); $tr = random_word(); print OUT "insert into buffy (name, team_role) values ( '$name', '$tr');\n"; if ( $i % 10000 == 0 ) { print "$i done\n"; } }
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Are passwords a dying breed?
Recently I was doing some discovery at work of some systems we inherited. I didn’t yet have access but wanted to determine what type of OS was involved so I could coordinate with the proper teams.
Continuing on LowEndBox’s community news features, the following piece is something that RackNerd recently sent over to us. Seeing that there are quite a bit of RackNerd customers from the LowEndBox & LowEndTalk community, as well as the fact that they are voted a top provider by the community, we feel that this was an impressive progress update worth reading, no doubt – RackNerd is certainly making lots of noise within the hosting industry lately, and I’d say that’s because of their aggressive growth and accomplishments that they’ve made throughout the years.
