After mariaDB 10.0 to 10.1 upgrade, mysql can no longer write tmpdir

Question

I ordered a new server that came with mariaDB 10.0 installed. I edited /etc/my.cnf to change the tmpdir to /home/mysql_tmp_dir (owned by mysql:mysql). All worked fine.

Did upgrade to mariaDB 10.1.37 and the tmpdir can no longer be written to:

[ERROR] mysqld: Can't create/write to file '/home/mysql_tmp_dir/ibV9SvJP' (Errcode: 13 "Permission denied")

This of course caused all kinds of problems, mainly that innodb engine was unable to load.

Commenting tmpdir out to revert to the default and restarting temporarily resolved the issue. But, I am at a loss as to why this happened and how to resolve it.

I need a larger tmpdir, otherwise it fills up when optimizing large databases, which of course causes mysql to lock up until space is freed.

Get your admin to place more temporary space in a proper place in the filesystem. /home is not a proper place for temp files, and many other things will not be able to write here either. — Michael Hampton, Jan 28 '19 at 04:03

score 1 · Answer 1 · answered Jan 28 '19 at 03:02

1

In earlier 10.1 release MariaDB added some systemd hardening, one of those was the setting to protect the homedir,

Try this

awk '/Protect/' /usr/lib/systemd/system/mariadb.service

If you see ProtectHome=true, you can either move the tmpdir somewhere else, or add

// File: /etc/systemd/system/mariadb.service.d/protecthome.conf
[Service]
ProtectHome=false

Related links

answered Jan 28 '19 at 03:02

Ryan Gibbons

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Thanks for the info. I will investigate further and try this solution. – vicos Jan 29 '19 at 04:17
I tried the ProtectHome=false and still was not able to write to home. – vicos Jan 30 '19 at 04:20
Never mind. All is well! I didn't do 'systemctl daemon-reload' before restarting mysql. – vicos Jan 30 '19 at 15:04

After mariaDB 10.0 to 10.1 upgrade, mysql can no longer write tmpdir

1 Answers1