disk space exhausts fast with Galera gcache.page.xxxxxx files

[Danil Akhmetov]

Detailed bug description:

MOS deployed with Fuel have a default MySQL and Galera configuration.

MySQL Galera creates it's cache files (gcache.page.xxxxxx where xxxxxx is incremental number), and leaving them. It's not possible to remove many of them because they are MMAPped by Galera. After free space exhausted on the disk where /var/lib/mysql located, the MySQL goes to read-only, so it's a critical issue.

Expected results:

Free space on the disk with /var/log/mysql is not exhausted with gcache.page.xxxxxx in default deployment.

Workaround:

Specify another path for gcache.page.xxxxxx, restart MySQL, clean /var/lib/mysql directory.

Impact:

Database goes read-only when free space exhausted.

Description of the environment:

Fuel-9-based environment, galera version: 25.3.10-1~u14.04+mos2.

Additional information:

seems to be fixed in 25.3.13: https://github.com/codership/galera/commit/4d54e1e6d28c966f8c82d99693ebdfebd44ef6a6

[Denis Meltsaykin (dmeltsaykin)]

MOS Linux team, could you please take a look at that?

[Dmitry Teselkin (teselkin-d)]

CR in 9.0 - https://review.fuel-infra.org/#/c/28287/

[Fuel Devops McRobotson (fuel-devops-robot)]

Reviewed: https://review.fuel-infra.org/28287
Submitter: Pkgs Jenkins <email address hidden>
Branch: 9.0

Commit: a8824dad44f158ba4ee90bf1982091361054b421
Author: Ivan Suzdal <email address hidden>
Date: Fri Nov 11 15:35:18 2016

Fix return value of gcache::Page::size

Patch sourced from [0]

[0] https://github.com/codership/galera/commit/4d54e1e6d28c966f8c82d99693ebdfebd44ef6a6

Change-Id: I657a768dd4f14ae741006d5ee4384711562ad8f6
Closes-Bug: #1640740

[TatyanaGladysheva (tgladysheva)]

Verified on 9.2 snapshot #516.