Category Archives: Databases

A NoSQL database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases.
A relational database management system is a database management system based on the relational model of data.

Redis: “psync scheduled to be closed ASAP for overcoming of output buffer limits” and the client-output-buffer-limit

26 February 2020
 

 We have a Redis-cluster with Master-slave replication and Sentinel, see the Redis: replication, part 2 – Master-Slave replication, and Redis Sentinel, Redis: fork – Cannot allocate memory, Linux, virtual memory and vm.overcommit_memory, and Redis: main configuration parameters and performance tuning overview posts. The system worked great until we started using it much more actively. Redis… Read More »

Chromium: Linux, keyrings && Secret Service, passwords encryption and store

10 December 2019
 

 One of the motives to go deeper into the keyrings (see the What is: Linux keyring, gnome-keyring, Secret Service, and D-Bus post) was the fact that Chromium, surprise-surprise, keep passwords unencrypted if a Linux system has no keyring and/or Secret Service enabled. So, let’s try to find how and where Chromium store passwords, and the… Read More »

Nextcloud: running in Docker Compose on Debian with Let’s Encrypt SSL

30 November 2019
 

 I while ago I’d tested the Nextcloud, see the NextCloud: installing server on Debian behind NGINX with PHP-FPM and client on Arch Linux post. In general, it looks good, so it’s time to try to run in a production environment and finally migrate from Dropbox to it. Today, let’s spin up a Nextcloud instance using… Read More »

AWS: RDS Certificate Authority SSL certificate upgrade

22 November 2019
 

 We started receiving emails from AWS with notifications to update RDS Certificate Authority certificates. It’s time to do it, so let’s start from our Dev, then will repeat on Staging and Production environments. W eare using common AWS RDS MariaDB instances, and the upgrade documentation is available here>>>. The process itself is really simple and… Read More »

AWS: Redshift – quick start and SQL-workbench connection config

18 October 2019
 

 Our data-analytics team eventually started to play with an AWS Redshift cluster instead of the MariaDB RDS service. Actually, the current task is to spin up a simple Proof of Concept Redshift’s cluster in the AWS. Let’s do it quickly, without details – if this will go to the Production, I’ll add another post with… Read More »

PostgreSQL: FATAL: Peer authentication failed for user “name”

11 September 2019
 

 A quick note mainly for myself on how to enable remote access in PostgreSQL and create its database dump. An EC2-server moved to our AWS account with one website. During an attempt to connect to the PostgreSQL running on this host – the “FATAL: Peer authentication failed for user “name”” appears. And the same error… Read More »

Redis: main configuration parameters and performance tuning overview

10 September 2019
 

 Currently configuring Redis server as our backend caching service and during that wrote this post with some things to pay attention at in Redis config file. Shortly enough but with links to other posts or documentation. Let’s begin with the redis-benchmark utility. Will be installed alongside with Redis service, so can be used right after… Read More »

SonarQube: solving “Unrecoverable indexation failures” and Elasticsearch “Disk watermark exceeded” errors

29 August 2019
 

 We are using SonarQube started from a Jenkins jobs. See more at SonarQube: running tests from Jenkins Pipeline in Docker. So, the SonarQube is started from the Jenkins – all good here, but inside SonarQube we can see errors: java.lang.IllegalStateException: Unrecoverable indexation failures: 1 errors among 1 requests at org.sonar.server.es.IndexingListener$1.onFinish(IndexingListener.java:39) at org.sonar.server.es.BulkIndexer.stop(BulkIndexer.java:122) … And host… Read More »

Redis: fork – Cannot allocate memory, Linux, virtual memory and vm.overcommit_memory

28 August 2019
 

 Currently, I’m configuring a Redis as a caching service for our application and during that, I faced with the question: do I need to set vm.overcommit_memory to the value 1, i.e. disable it – or not? The question is quite old for me, see The story, but only now I found time to get to… Read More »