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High Availability Solutions for Databases?

Posted by Cliff on from the in-search-of-redundancy dept.

An anonymous reader asks: "What would be the best high availability solution for databases? I don't have enough money to afford Oracle RAC or any architecture that require an expensive SAN. What about open source solutions? MySQL cluster seems to be more master/slave and you can lose data when the master dies. What about this Sequoia project that seems good for PostgreSQL and other databases? Has anyone tried it? What HA solution do you use for your database?"

2 of 83 comments (clear)

  1. MySQL Cluster != master/slave by cravey · · Score: 5, Informative

    While MySQL supports master/slave replication, MySQL Cluster specifically avoids that entire model. It's an entirely synchronous database storage engine. If you want master/slave, use postgres. If you want high availability and can handle the lack of a small number of features, MySQL Cluster is the way to go. The only real downside to the architecture required for CLuster is that all of the data is stored in RAM based tables. transactions are logged to disk every (configurable) time interval. If you're going to try for HA, you might want to RTFM on the available options before you settle on one.

  2. What are you doing? It's important. by anon+mouse-cow-aard · · Score: 5, Insightful

    It's odd that all these people are answering without hearing a thing about your application. How big is the db? How often is it written? How often is it read?

    For example, we run a site with data from a thousand odd different data sources, with each source getting updated every hour or so. We do it by parsing the data into static pages. We we receive a datum, we rebuild the pages that depend on it.

    We have another site that runs off an Oracle db. the static page site runs about 90x faster, and is basically in memory (disk access is nil.) Now take into account that we can (and do) replicate the static page solution with zero load, we get to a solution that is literally 900x faster.

    Now folks are thinking 'oh, the horror!' well... tough! There is no substitute for thinking about your data, and how it flows. A DB is not a given, but a (potentially wrong) answer to a question after you have done some analysis.