Showing entries 31 to 40 of 145
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: Percona XtraDB Cluster (reset)
A first look at RDS Aurora

Recently, I happened to have an onsite engagement and the goal of the engagement was to move a database service to RDS Aurora. Like probably most of you, I knew the service by name but I couldn’t say much about it, so, I Googled, I listened to talks and I read about it. Now that my onsite engagement is over, here’s my first impression of Aurora.

First, let’s describe the service itself. It is part of RDS and, at first glance, very similar to a regular RDS instance. In order to setup an Aurora instance, you go to the RDS console and you either launch a new instance choosing Aurora as type or you create a snapshot of a RDS 5.6 instance and migrate it to Aurora. While with a regular MySQL RDS instance you can create slaves, with Aurora you can add reader nodes to an existing cluster. An Aurora cluster minimally consists of a …

[Read more]
Proxy Protocol and Percona XtraDB Cluster: A Quick Guide

On September 21st, we released Percona XtraDB Cluster 5.6.25. This is the first PXC release supporting proxy-protocol that has been included in Percona Server since 5.6.25-73.0.

With this blog post, I want to promote a new feature that you may have ignored.

Let’s start with a description of the use case:

Architecture Overview:

HAProxy is configured like this:

listen 3307-active-passive-writes 0.0.0.0:3307
    mode tcp
    balance …
[Read more]
Percona XtraDB Cluster 5.6.26-25.12 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on October 15th 2015. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.26-74.0 including all the bug fixes in it, Galera Replicator 3.12, and on …

[Read more]
Percona XtraDB Cluster 5.6.25-25.12 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on September 21st 2015. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.25-73.1 including all the bug fixes in it, Galera Replicator 3.12, and on …

[Read more]
Clarification on “Call me Maybe: MariaDB Galera Cluster”

Recently Aphyr (Kyle Kingsbury) published https://aphyr.com/posts/327-call-me-maybe-mariadb-galera-cluster

The article is technically valid, I am not going to dispute a conclusion Aphyr made, but it is also quite technically involved, so users who just jump to conclusion may get the wrong impression and we’re left with more questions than ever.

So, let me state what is the real conclusion of this article:
“Galera cluster does not support SNAPSHOT ISOLATION LEVEL, in contract to what was stated in the documentation”.
Following that conclusion is using Galera cluster may result in “corrupted” data.

I do not quite like the usage of the word “corrupted” here. For me, the more correct word be to use is “inconsistent”.

So with this clarification, the …

[Read more]
High-load clusters and desynchronized nodes on Percona XtraDB Cluster

There can be a lot of confusion and lack of planning in Percona XtraDB Clusters in regards to nodes becoming desynchronized for various reasons.  This can happen a few ways:

When I say “desynchronized” I mean a node that is permitted to build up a potentially large wsrep_local_recv_queue while some operation is happening.  For example a node taking a backup would set wsrep_desync=ON during the backup and potentially fall behind …

[Read more]
Optimizing PXC Xtrabackup State Snapshot Transfer

State Snapshot Transfer (SST) at a glance

PXC uses a protocol called State Snapshot Transfer to provision a node joining an existing cluster with all the data it needs to synchronize.  This is analogous to cloning a slave in asynchronous replication:  you take a full backup of one node and copy it to the new one, while tracking the replication position of the backup.

PXC automates this process using scriptable SST methods.  The most common of these methods is the xtrabackup-v2 method which is the default in PXC 5.6.  Xtrabackup generally is more favored over other SST methods because it is non-blocking on the Donor node (the node contributing the backup).

The basic flow of this method is:

  • The Joiner:
    • joins the cluster …
[Read more]
PXC – Incremental State transfers in detail

IST Basics

State transfers in Galera remain a mystery to most people.  Incremental State transfers (as opposed to full State Snapshot transfers) are used under the following conditions:

  • The Joiner node reports Galera a valid Galera GTID to the cluster
  • The Donor node selected contains all the transactions the Joiner needs to catch up to the rest of the cluster in its Gcache
  • The Donor node can establish a TCP connection to the Joiner on port 4568 (by default)

IST states

Galera has many internal node states related to Joiner nodes.  They currently are:

  1. Joining
  2. Joining: preparing for State Transfer
  3. Joining: requested State Transfer
  4. Joining: receiving State Transfer
  5. Joining: State …
[Read more]
Bypassing SST in Percona XtraDB Cluster with binary logs

In my previous post, I used incremental backups in Percona XtraBackup as a method for rebuilding a Percona XtraDB Cluster (PXC) node without triggering an actual SST. Practically this reproduces the SST steps, but it can be handy if you already had backups available to use.

In this post, I want to present another methodology for this that also uses a full backup, but instead of incrementals uses any binary logs that the cluster may be producing.

Binary logs on PXC

Binary logs are not strictly needed in PXC for replication, but …

[Read more]
Bypassing SST in Percona XtraDB Cluster with incremental backups

Beware the SST

In Percona XtraDB Cluster (PXC) I often run across users who are fearful of SSTs on their clusters. I’ve always maintained that if you can’t cope with a SST, PXC may not be right for you, but that doesn’t change the fact that SSTs with multiple Terabytes of data can be quite costly.

SST, by current definition, is a full backup of a Donor to Joiner.  The most popular method is Percona XtraBackup, so we’re talking about a donor node that must:

  1. Run a full XtraBackup that reads its entire datadir
  2. Keep up with Galera replication to it as much as possible (though laggy donors don’t send flow control)
  3. Possibly still be serving application traffic if you don’t remove Donors from rotation.
[Read more]
Showing entries 31 to 40 of 145
« 10 Newer Entries | 10 Older Entries »