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Displaying posts with tag: node (reset)
MySQL High Availability Framework Explained – Part III: Failure Scenarios

In this three-part blog series, we introduced a High Availability (HA) Framework for MySQL hosting in Part I, and discussed the details of MySQL semisynchronous replication in Part II. Now in Part III, we review how the framework handles some of the important MySQL failure scenarios and recovers to ensure high availability.

MySQL Failure Scenarios Scenario 1 – Master MySQL Goes Down

  • The Corosync and Pacemaker framework detects that the master MySQL is no longer available. Pacemaker demotes the master resource and tries …
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Highly Available Redis Clusters with Automated Sharding Launches at ScaleGrid

PALO ALTO, Calif., January 24, 2019 – ScaleGrid, a rising leader in the Database-as-a-Service (DBaaS) space, has just announced support for Redis Clusters on their fully managed Redis hosting plans. Redis Cluster is the native sharding implementation available within Redis, an open-source in-memory data structure project, that allows you to automatically shard across multiple Redis nodes without having to rely on external tools and utilities.

ScaleGrid is no novice when it comes to deploying and managing complex, sharded clusters in the cloud, as they have provided one of the most powerful sharding tools for their MongoDB hosting solutions since 2013.

With the introduction of Redis Clusters at ScaleGrid, Redis users can now easily create sharded clusters …

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MySQL High Availability Framework Explained – Part II: Semisynchronous Replication

In Part I, we introduced a High Availability (HA) framework for MySQL hosting and discussed various components and their functionality. Now in Part II, we will discuss the details of MySQL semisynchronous replication and the related configuration settings that help us ensure redundancy and consistency of the data in our HA setup. Make sure to check back in for Part III where we will review various failure scenarios that could arise and the way the framework responds and recovers from these conditions.

What is MySQL Semisynchronous Replication?

Simply put, in a …

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MySQL High Availability Framework Explained – Part I

In this three-part blog series, we will explain the details and functionality of a High Availability (HA) framework for MySQL hosting using MySQL semisynchronous replication and the Corosync plus Pacemaker stack. In Part I, we’ll walk you through the basics of High Availability, the components of an HA framework, and then introduce you to the HA framework for MySQL.

What is High Availability?

The availability of a computer system is the percentage of time its services are up during a period of time. It’s generally expressed as a series of 9′s. For example, the table below shows availability and the corresponding downtime measured over one year.

Availability %
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A small dive into the MySQL 8.0 X-DevAPI


What is the X-DevApi? From there is a definition of the X-DevAPI and its features in the following paragraphs:

The X DevAPI is the common client-side API used by all connectors to abstract the details of the X Protocol. It specifies the common set of CRUD-style functions/methods used by all the official connectors to work with both document store collections and relational tables, a common expression language to establish query properties such as criteria, projections, aliases, and a standard set of additional database management features for handling things like transactions, indexes, etc.

The fact that most of these features share the same format and API between connectors, makes the X DevAPI a perfect fit for modern polyglot development environments such as microservices, and the fact that they are based on a …

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Data Integrity and Performance Considerations in MySQL Semisynchronous Replication

MySQL semisynchronous replication provides improved data integrity because when a commit returns successfully, it’s known that the data exists in at least two places – the master and its slave. In this blog post, we review some of the MySQL hosting configurations that influence the data integrity and performance aspects of semisynchronous replication. We’ll be using InnoDB storage engine and GTID-based replication in a 3-node replica set (master and 2 slaves), which will ensure there is redundancy in the slaves. This means that if there are issues with one slave, we can fall back on the other.

Configurations Applicable to Both Master and Slave Nodes

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Faster Node Rejoins with Improved IST performance

In this blog, we’ll look at how improvements to Percona XtraDB Cluster improved IST performance.


Starting in version 5.7.17-29.20 of Percona XtraDB Cluster significantly improved performance. Depending on the workload, the increase in throughput is in the range of 3-10x. (More details here). These optimization fixes also helped improve IST (Incremental State Transfer) performance. This blog is aimed at studying the IST impact.


IST stands for incremental state transfer. When a node of the cluster leaves the cluster for a short period of time and then rejoins the cluster it needs to catch-up with cluster state. As part of this sync …

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What engineering roles are most in demand at startups?

via GIPHY I was just reading over StackOverflow’s 2017 Developer survey. As it turns out there were some surprising findings. Join 33,000 others and follow Sean Hull on twitter @hullsean. One that stood out was databases. In the media, one hears more and more about NoSQL databases like Cassandra, Dynamo & Firebase. Despite all that … Continue reading What engineering roles are most in demand at startups? →

The Uber Engineering Tech Stack, Part II: The Edge and Beyond

Uber Engineering

Uber’s mission is transportation as reliable as running water, everywhere, for everyone. Last time, we talked about the foundation that powers Uber Engineering. Now, we’ll explore the parts of the stack that face riders and drivers, starting …

The post The Uber Engineering Tech Stack, Part II: The Edge and Beyond appeared first on Uber Engineering Blog.

My experience with node and mongodb course "M101JS: MongoDB for Node.js Developers" (Third Week)

Well, currently I am into the third week of mongodb node course "M101JS: MongoDB for Node.js Developers" and I am pretty enjoying it.

Lots of personal learning into node and mongodb.

The third week subject of "Patterns, Case Studies & Tradeoffs" is really interesting.

Here is a list of topics, I learned about:
- Mongodb rich documents concept.
- Mongodb schema use cases.
- Mongodb one:one, one:many, many:many use cases.
- How to select schema based on the usage like whether you want max performance
  or it may be a tradeoff.

One important point, I learned during the course is:
"While relational databases usually go for the normalised 3rd form so that data usage is agnostic to application, but mongodb schema arrangement is very closely related to application usage and varies accordingly."

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