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Showing entries 1 to 10 of 30 10 Older Entries

Displaying posts with tag: System Administration (reset)

Working with CloudFlare DNS in python
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Last week I wrote about aDNS discovery feature in Etcd. As a step in the whole process we need to create DNS records in twindb.com zone. CloudFlare provides rich API to work with it. We wrapped it into a Python module twindb_cloudflare and opensourced it:

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Setting up Etcd cluster with DNS discovery
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Setting up an etcd cluster with DNS discovery may be challenging. There are several building blocks:

  • Etcd – a distributed key value store
  • Amazon EC2 – cloud computing provider
  • Cloudflare – DNS provider
  • Chef – for configuring individual nodes

Each of them has their pitfalls, we will guide you through whole process.

DNS discovery

Any clustered system needs a way to maintain a list of nodes in a cluster. Usually you need to specify all cluster members when starting a node. This is the way …

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Data loss after MySQL restart
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Not so long ago I had a customer who experienced data loss after MySQL restart. It was really puzzling. MySQL was up & running for many months, but after the customer restarted MySQL server all tables have gone. The tables were still visible in SHOW TABLES output, but they were not readable:

mysql> show tables like 'actor';
+--------------------------+
| Tables_in_sakila (actor) |
+--------------------------+
| actor                    |
+--------------------------+
1 row in set (0.00 sec)

mysql> select * from actor;
ERROR 1146 (42S02): Table 'sakila.actor' doesn't exist
mysql>


To understand …

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Encrypting MySQL Backups
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Encryption is important component of secure environments. While being intangible property security doesn’t get enough attention when it comes to describing various systems. “Encryption support” is often the most of details what you can get asking how secure the system is. Other important details are often omitted, but the devil in details as we know. In this post I will describe how we secure backup copies in TwinDB.

See the picture. This is what happens when encryption is used incorrectly. The encryption algorithm can be perfect, but poor choice …

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Xtrabackup and MySQL 5.6 on Amazon instance
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Have you ever tried to install Xtrabackup on Amazon EC2 instance with Oracle’s MySQL 5.6? Dependencies hell strikes when you ask pretty common and reasonable thing – run the GA version of MySQL and backup it with the most popular open-source tool – XtraBackup. From this post you will learn how to resolve the conflicts and make everybody happy.

mysql55-libs conflicts with mysql-community-libs-5.6.22

A fresh Amazon Linux AMI, 2014.09 EC2 instance comes with MySQL 5.5.40 in amzn-updates repository. Today MySQL 5.5 turns five years old. It’s a good and stable version. But many people want to run MySQL 5.6, because it’s better than …

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Temporary table naming scheme in 5.6 and before
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Benchmarking is a popular topic. People love drawing graphs as much as watching how X is 10% faster than Y; there must be something special in measurements.

For a DBA, however, more tangible improvements come from less popular area of database maintenance. While MariaDB spreads FUD around InnoDB (nonetheless still uses it) I have to admit InnoDB gets more friendly to DBAs.

In MySQL 5.6 new temporary table naming scheme was introduced – one of …

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Resolving ERROR 1050 (42S01) at line 1: Table ‘sakila/#sql-ib712′ already exists
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When ALTER TABLE crashes MySQL server it leaves orphaned records in InnoDB dictionary. It is annoying because next time you run the same ALTER TABLE query it will fail with error:

ERROR 1050 (42S01) at line 1: Table 'sakila/#sql-ib712' already exists

The post explains why it happens and how to fix it.

When you run ALTER table InnoDB follows the plan:

  1. Block the original table
  2. Create an empty temporary table with the new structure. The name of the new table is something like #sql-ib712.
  3. Copy all records from the original table to the temporary one
  4. Swap the …
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Installing MySQL on Mac OS X easily
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Installing MySQL Database on Ubuntu or CentOS is a trivial operation as long as they have nice package managers as Aptitute and YUM. Otherwise, in Mac OS X is a hard operation from downloading the correct package, apllying with several steps and it can break the whole install, if you But, with Homebrew, the install... Read More

The post Installing MySQL on Mac OS X easily appeared first on Devops for Dummies.

The network is reliable
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A fascinating post-mortem on high profile network failures:

This post is meant as a reference point–to illustrate that, according to a wide range of accounts, partitions occur in many real-world environments. Processes, servers, NICs, switches, local and wide area networks can all fail, and the resulting economic consequences are real. Network outages can suddenly arise in systems that are stable for months at a time, during routine upgrades, or as a result of emergency maintenance. The consequences of these outages range from increased latency and temporary unavailability to …

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Stuck at "copying to tmp table"
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I have a fairly lightly loaded MySQL server with a few tables that are updated every five minutes. Other than these updates, there are very few queries run against the database. The data is queried just a few times per month. Ever so often, one of the more complicated queries will result in the process getting hung in the "copying to tmp table" state. To be honest, the queries that get hung aren't even that complicated. Usually there's one or two joins, a GROUP BY, and an ORDER BY.

So far, when a process gets stuck in this state, I find that killing and …

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Showing entries 1 to 10 of 30 10 Older Entries

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