With the tmp partition full, the server will experience many random issues such as server crashes. Your sites will quickly go down and leave you head-scratching.

Fortunately, it's quite easy to resize the /tmp partition on cPanel servers — especially if it is the default one created by cPanel installs. There's a handy script at /scripts/securetmp.

Open this file:

pico /scripts/securetmp


And find this line:

my $tmpdsksize = 512000; # Must be larger than 250000


Change it to a larger number than 512 MB. Say you want it to be 2 GB:

my $tmpdsksize = 2097152; # 2GB for the /tmp folder


Now close and save the file.

We need to stop all services that may be using this folder. For me, this includes MySQL, Apache and Nginx.

service mysql stop
service nginx stop
service httpd stop


Now we will simply unmount the /tmp folder and recreate it. Here's the sequence of commands to create it:

lsof /tmp
umount -l /tmp
umount -l /var/tmp
rm -fv /usr/tmpDSK
/scripts/securetmp


Done. You can verify the size of the /tmp folder among others:

df -h


This should show you something like this:

...
/usr/tmpDSK ext3 2.0G 996M 1.1G 51% /tmp
...


NOTE: If you have any problems, for instance, the size of the recreated /tmp folder is not really 2GB despite that code in the /scripts/securetmp we changed, it may be because of some settings you have in the /etc/fstab file. Take a look at it and comment out any lines that interfere with the LABEL for /tmp mount.

The recent upgrades of Cpanel have been a pain because they've broken mysqlhotcopy. Not kosher. Fortunately fixing this is pretty easy, by simply downgrading the DBD module of Perl, which mysqlhotcopy relies on.

Usually the error is something like this:

To solve this, simply downgrade the DBD to version 4.001. Create a script anywhere on your root folder as, say, dbd-downgrade.sh:

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#!/bin/sh
cd /usr/src
wget -O dbd.tar.gz  "http://search.cpan.org/CPAN/authors/id/C/CA/CAPTTOFU/DBD-mysql-4.001.tar.gz"
gzip -cd dbd.tar.gz | tar xf -
rm -rf dbd.tar.gz
cd DBD-mysql-4.001
perl Makefile.PL
make
make install

Then of course chmod the file to executable (644) and run it:

Then try your mysqlhotcopy command again. It should work. The only thing to consider is that if your Cpanel is setup to upgrade automatically, it may rebuild DBD. You may need to downgrade the DBD again, until this thing is fixed!

If after this update, you see the error for RELOAD privileges, like this…

DBD::mysql::db do failed: Access denied; you need the RELOAD privilege for this operation at /usr/bin/mysqlhotcopy line 472.

…then simply login to mysql as "root" user through the root SSH terminal, and execute the following command:

mysql>  grant all privileges on *.* to root@localhost;
mysql>  flush privileges;

Done. That should do it. Let me know if it doesn't.

A more long term fix

MySQL bug list has a couple of suggested fixes. If you are comfortable with Perl, you can edit the code in /usr/bin/mysqlhotcopy and have it solved in a better way.