I'm using Ubuntu 18.04 LTS 64-bit and I'm really been struggling with this - can anyone tell me where I'm going wrong?

I've had my MySQL files on a separate big disk for ages but the said big disk died suddenly. So I put a new disk in new and gleaming 3TB of it. For complicated reasons to do with a company whose name reminds you of a big South American river I actually ended up with 2 3TB disks.

I had to reinstall the server as all the copies of my data directory had got clobbered. I did have backups of my databases, don't worry.

However after reinstalling the server and changing the apparmor file and the data files directory as described in various places as I had before, mysql won't start.

If I try sudo /usr/sbin/mysqld it says:

2019-09-20T09:35:09.083922Z 0 [Note] /usr/sbin/mysqld (mysqld 5.7.27) starting as process 16284 ... 2019-09-20T09:35:09.085612Z 0 [ERROR] Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root!

If I try setting it back everything is fine. But the /var/lib/mysql filesystem isn't big enough.

I've tried keeping the mysql config the same and doing a symlink from /var/lib/mysql to /bigdisk/mysql that still fails. All the permissions seem right

Please help because I've just had 2 big disks put in and I can't use them!

I noticed that I now seem to be dealing with MySQL "community server" does that mean anything?

  • 1
    Which LTS release of Ubuntu are you talking about?
    – guiverc
    Sep 20, 2019 at 12:00
  • Sorry 18.04 don't know how that got wiped Sep 20, 2019 at 12:23
  • You shouldn't run MySQL as root; it should run as its own user (mysql) which you accomplish by starting it with sudo systemctl start mysql. The symlink solution is in your case probably the best; what message do you get if you try it that way? Finally: the "community server" is indeed what you need.
    – Jos
    Sep 20, 2019 at 13:28
  • I tried that and it still failed on startup. No particular explanation but "dmesg" has as final line :[29884.356109] audit: type=1400 audit(1568993017.872:998): apparmor="DENIED" operation="capable" profile="/usr/sbin/mysqld" pid=23472 comm="mysqld" capability=2 capname="dac_read_search" [29884.379316] audit: type=1400 audit(1568993017.896:999): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=23474 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=121 ouid=0 Sep 20, 2019 at 15:28

1 Answer 1


Apologies after all that wrestling the solution was very simple.

When I formatted the disks (from the "disks" gui it helpfull created the root directory owned by me (so I could see things in it as well as root but no one else) and with permissions 700.

Makde that 755 owned by root and all was sweetness and light.

Typically I discovered that doing something else (trying to get Virtualbox to work).

So sorry for annoying everyone.

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