[CentOS] MySQL error 28, can't write temp files - how to debug?

Hi all,

I hope someone can help with this one.

On one of our VPS's we have a fairly large MySQL database, which gives
me the following error when running some queries against it:



An error occured!Can't execute statement: Error writing file
'/tmp/MYL4qeT5' (Errcode: 28)
SQL: , , select * from tips order by rand() limit 0, 1 ,



According to google search, errorcode 28 means the HDD is full. But it isn't:


root at vps:[~]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              84G   18G   62G  23% /
none                  640M     0  640M   0% /dev/shm
/usr/tmpDSK           485M   11M  449M   3% /tmp


What else could cause this kind of problem?

-- 
Kind Regards
Rudi Ahlers
CEO, SoftDux Hosting
Web: http://www.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532