High Availability

Today’s global and distributed applications often need to serve user requests from a single data source across different regions. While providing data scaling and protection against network outages, ensuring low-latency access to data is critical for providing a seamless user experience. YugabyteDB, a distributed SQL database, is designed to handle global data workloads efficiently. In this blog post, I’ll share some techniques to optimize read and write latency in a multi-region YugabyteDB cluster.

I was recently reviewing a database partitioning definition in YugabyteDB (the postgres “ysql” API), and realized the partition distribution might not be what the developer intended.

What is database partitioning?

Database partitioning is used to divide large tables into smaller tables (partitions). While the data is physically separate, the application can access the data logically as a single table.

This can help performance through a process called partition pruning. The database planner skips partitions that don’t hold the data. For example, if a table is partitioned on months of the year, a query on a single month only has to access the rows in the single partition for that month.

I’m writing this the night before we’re going to get some very bad weather. In North Carolina this time of year, that could mean an ice storm. Ice coats all the big and little branches on all the trees, and then they start to shatter onto roofs and overhead cables. I’ve lived all over the lower 48 and in Alaska, and ice storms are by far the worst, especially in a state that doesn’t bury the electrical lines.

A distributed database is designed to withstand outages to a good degree. However, you should also maintain backups in case of “oops” scenarios like a dropped table.

The yb-admin tool can be used to manage snapshots. Here’s a brief walkthrough.

Some caveats about using snapshots… They are stored on the same server, so this method doesn’t protect against file system corruption. Also, this doesn’t snapshot the schema, just data.

If you don’t already have a test environment, check out a quick test setup here https://github.com/dataindataout/xtest_ansible.

Gearing up for my next YFTT presentation next month. It will be on fuzzy matching, a chance to show out some neat string search features.

Meanwhile, here’s the deck for my last YFTT. The topic was audit logging.

https://info.yugabyte.com/hubfs/YFTT%20Slide%20Decks/2022_12_02_YFTT_Valerie%20Parham-Thompson_Audit%20Logging%20in%20YugabyteDB.pdf

Audit logging is just one of the security features available in YugabyteDB. You can use it to tell you the “who, what, when, where” of actions on your systems. The logs can be then sent to a log analysis system for archiving and correlation with other logs.

Here’s a very quick way to set up YugabyteDB on your Mac for functional testing. It assumes you already have Homebrew installed.

brew tap yugabyte/yugabytedb
brew install yugabytedb

In the future, you can upgrade the version by running this:

brew upgrade yugabytedb

Verify the installation and check the version:

yugabyted version

Set up local networking:

sudo ifconfig lo0 alias 127.0.0.2
sudo ifconfig lo0 alias 127.0.0.3

Then you can set up a three-node YugabyteDB cluster. Change the data directory if you’d like.

PostgreSQL offers multiple backup options, including logical backups with pg_dump and pg_dumpall, and physical backups with pg_basebackup. Regular backups and testing restore procedures are essential for disaster recovery. Continuous archiving and point-in-time recovery provide additional protection and flexibility for critical database environments.

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Nodetool is a powerful administrative tool for Cassandra, offering commands for cluster management, monitoring, and maintenance. Learning nodetool basics is essential for new administrators to effectively manage and troubleshoot distributed databases.

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Nodetool provides detailed information about Cassandra cluster status, node health, and performance metrics. Using nodetool commands helps administrators monitor and troubleshoot clusters, ensuring smooth operation and quick resolution of issues.

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The nodetool utility in Cassandra enables snapshot creation and restoration for backups. Best practices include scheduling regular snapshots, testing restore procedures, and ensuring data consistency. This approach is essential for disaster recovery planning and data protection.

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