• mylvmbackup HOWTO: minimal privileges & filesystem copy

    August 17, 2010

    This HOWTO discusses two (unrelated) issues with mylvmbackup: The minimal privileges required to take MySQL backups with mylvmbackup. Making (non compressed) file system copy of one's data files. Minimal privileges Some just give mylvmbackup the root account, which is far too permissive. We now consider what the minimal requirements of mylvmbackup are. The queries mylvmbackup […]

  • MMM for MySQL single reader role

    August 12, 2010

    The standard documentation and tutorials on MMM for MySQL, for master-master replication setup, suggest one Virtual IP for the writer role, and two Virtual IPs for the reader role. It can be desired to only have a single virtual IP for the reader role, as explained below. The two IPs for the reader role A […]

  • Table refactoring & application version upgrades, Part II

    August 12, 2010

    Continuing Table refactoring & application version upgrades, Part I, we now discuss code & database upgrades which require DROP operations. As before, we break apart the upgrade process into sequential steps, each involving either the application or the database, but not both. As I'll show, DROP operations are significantly simpler than creation operations. Interestingly, it's […]

  • Another Python MySQL template

    August 11, 2010

    Following up on Matt Reid's simple python, mysql connection and iteration, I would like to share one of my own, which is the base for mycheckpoint & openark kit scripts. It is oriented to provide with clean access to the data: the user is not expected to handle cursors and connections. Result sets are returned […]

  • Table refactoring & application version upgrades, Part I

    August 10, 2010

    A developer's major concern is: How do I do application & database upgrades with minimal downtime? How do I synchronize between a DB's version upgrade and an application's version upgrade? I will break down the discussion into types of database refactoring operations, and I will limit to single table refactoring. The discussion will try to […]

  • Tips for taking MySQL backups using LVM

    August 3, 2010

    LVM uses copy-on-write to implement snapshots. Whenever you're writing data to some page, LVM copies the original page (the way it looked like when the snapshot was taken) to the snapshot volume. The snapshot volume must be large enough to accommodate all pages written to for the duration of the snapshot's lifetime. In other words, […]

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