SolusVM displaying wrong disk usage statistics for Xen PV VMs

Recently some of our Xen PV VMs started to show strange disk space usage statistics in SolusVM – despite there being plenty of space left on the disk in the VM, SolusVM was reporting that the disk was nearly full!

I struggled to find any public information about this, but apparently it is a known problem with SolusVM and the version of the “df” utility used in RHEL/CentOS 6.5. There have been some slight changes to the way that df displays its output and this causes SolusVM to interpret the disk usage figures incorrectly.

SolusLabs have posted a workaround for this at http://bin.soluslabs.com/1083/38662948/raw/ and I’m reproducing it here for posterity as well as in the hope that it will get indexed:

Fix for Xen PV disk usage showing 100% when using a CentOS 6.5 host node
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The “df” output in CentOS 6.5 has changed. You may notice this when you upgrade you’re host node from CentOS 6.4. All the Xen PV virtual servers will show 100% disk space used.

On the affected host node edit /usr/local/solusvm/data/advanced.conf and add the following line:

XENFIXCENTOS6DF=”1″

Then run these commands:

wget https://www.dropbox.com/s/j8nu3ye09x9ehwq/command.php -O /usr/local/solusvm/www/command.php
wget https://www.dropbox.com/s/93hsnzzmpwny3r4/solusvmc-xen -O /usr/local/solusvm/core/solusvmc-xen
chmod 6777 /usr/local/solusvm/core/solusvmc-xen

Now when you reboot a virtual server (with the reboot button) the disk usage should update correctly.