MySQL error: "The partition with /var/lib/mysql is too full!" df -h shows otherwise

Question

my rented server is currently saying that mysql is too full when trying to start it when using /etc/init.d/mysql start. However using sudo /etc/init.d/mysql start it works normally.

Running df -h shows that there are no full partitions

Filesystem      Size  Used Avail Use% Mounted on
rootfs           20G  1.5G   17G   9% /
/dev/root        20G  1.5G   17G   9% /
devtmpfs         32G  4.0K   32G   1% /dev
none            4.0K     0  4.0K   0% /sys/fs/cgroup
none            6.3G  752K  6.3G   1% /run
none            5.0M     0  5.0M   0% /run/lock
none             32G     0   32G   0% /run/shm
none            100M     0  100M   0% /run/user
/dev/md2        127G   11G  111G   9% /home

as requested df -i

Filesystem      Inodes  IUsed   IFree IUse% Mounted on
rootfs         1281120  45568 1235552    4% /
/dev/root      1281120  45568 1235552    4% /
devtmpfs       8242291   1516 8240775    1% /dev
none           8250649      2 8250647    1% /sys/fs/cgroup
none           8250649   1031 8249618    1% /run
none           8250649      1 8250648    1% /run/lock
none           8250649      1 8250648    1% /run/shm
none           8250649      2 8250647    1% /run/user
/dev/md2       8462336 990512 7471824   12% /home

I am confused because mysql claims its full when restarting normally, but then lets me restart it when using sudo, and df -h shows that there is plenty of space.

Thank you for the help.

Solution

Always control services as root.

While you can log in as root to control a service, it isn't recommended.

Instead, use either:

sudo /etc/init.d/mysql restart

Or:

su -c "/etc/init.d/mysql restart"

The former requires the logged in user to be configured within sudo. This involves being a member of a certain group - the group depends on the distro. The advantage is that the user will be using their own password.

The latter will involve the logged in user having the root password to run the command.

Comments

[Dom]

Could you add a df -i ?

[jjacobson]

@Dom added df -i

[garethTheRed]

What do you mean "restarting normally, but then lets me restart it when using sudo"? Exactly what is "restarting normally"?

[Pratap]

Can you provide exact error with the restart command which you are using to restart?

[jjacobson]

@garethTheRed When not using sudo it fails to start and I get /etc/init.d/mysql: ERROR: The partition with /var/lib/mysql is too full!

[jjacobson]

@PratapSingh I get /etc/init.d/mysql: ERROR: The partition with /var/lib/mysql is too full!

[garethTheRed]

What command do you use when you're not using sudo?

[Pratap]

in your df command we do not see any partition as /var/lib/mysql ? Can you check what is your datadir in my.cnf? provide output of command "ls -ald /var/lib/mysql/"

[jjacobson]

@PratapSingh That outputs drwx------ 7 mysql mysql 4096 Sep 17 02:31 /var/lib/mysql/

[jjacobson]

@garethTheRed The same command but without sudo "/etc/init.d/mysql restart"

[garethTheRed]

But are you logged in as a normal user or as root? If the latter, why are you using sudo as root? (other than because it works of course!)

[jjacobson]

@garethTheRed That's actually a good point. I was logged in as a normal user. Would that cause the "is full" error?

[garethTheRed]

I would expect it to complain about Permissions. I've just installed it on a Ubuntu VM and it does indeed also compain about the partition being too full! How odd :-). Anyway, always restart it as root and you'll be fine.

[jjacobson]

Wow thanks @garethTheRed That is really weird that it says its full.

[jjacobson]

Thanks a lot for the help @PratapSingh, looks like it was a weird permissions thing. I am not sure why it would use that as the complaint instead of not having permissions.