Voice mail prompts slurring in FreePBX running under VMWware

We have installed FreePBX on a virtual server, under VMware

The system is in trial mode, with around 30 extensions and 1
trunk, and is performing well, with one significant exception that is delaying
our roll-out to the users

When installed on a server with other virtuals running,
voicemail prompts are slurred, i.e. when playing back, the voice pauses, then
starts again, then pauses etc.  This occurs
randomly on most (but not all) calls, but on some at least every 2 – 3 minutes.

If we move the virtual to our test server, and run it
without any other virtuals on that hardware, the problem disappears.

We suspect the system is being interrupted by disk activity
(or something else) from other virtuals on the server, but have not been able
to confirm this, or find a setting that fixes it.

The FreePBX virtual setup includes 8,800MHz CPU reserved,
8,192G Memory reserved, Hard disk share set at High (share value 2000, all others
at 1,000). It has 4 CPU allocated, and Thick Disk Provisioning of 1,000G.  We therefore don’t believe the application is
being constrained by the available resources in the normally understood manner.

We have not installed VMware tools on the virtual, to avoid
any timing issues from that.

The FreePBX is a new install using the 64Bit FreePBX 2.11 Linux
6.5 downloaded ISO.

When browsing these and the Asterisk forums there is much
conflicting information whether this should be run in a virtualised
environment, but recent posts seem to indicate many are doing this now.  We believe having to downgrade to a
stand-alone server would be a significantly backward step for system support
(all our company servers are now virtualised), so would like to explore all
available options first – but have run out of ideas ourselves.

Can anyone advise us? 
I am happy to post config files, if someone points me to which ones would
be relevant.

Respectfully, I have been using “virtualised” PBX’i for a long time and under many schedulers , save yourself money and grief and just go with Linux’ KVM/QEMU, it’s free and it works and there are any number of front ends to manage it, tuning proprietary VMWare or Hyper-V to make them work with Asterisk just shouldn’t belong in these forums, they have their own places to sort that out.


Thanks for your note Dicko, stating your preference for a
different virtualising platform, however I am seeking assistance with the setup
of FreePBX on VmWare (which, by the way is also free).

I know there are many installations of FreePBX running under
this configuration, as there have been questions answered in these forums, but
not relating to my problem.

As I have stated also numerous times and as the lead dev on the FreePBX Distro do not virtualize this in VMWare, Virtual Box or Hyper-V. You are asking for nothing but problems. If you must use virtualization which is tough to begin with on real time voice traffic use a proper KVM setup. This is coming from a company with thousands of customers on our hosted platform and knowing what works and does not. Please listen to what I have said and Dicko. Save yourself a ton of headaches.

Thanks Tony – we have seen similar messages, but also seen
many contributions that seem to indicate that later reversions of VMWare
resolve most issues.

Given your status, we accept your advice and are now seeking
an appropriate hardware platform to dedicate to the FreePBX deployment.

Which version of VMware are you running. I’ve run FreePBX under VMware without issue before now. However if you are running VMware ESXi 4.x you may well get timing issues. Also how heavily loaded is the physical server that your VM is running on. If this is very heavily loaded then again you might be getting timing issues.

Also a lot depends on your hardware’s capabilities. Have a look at this: http://blogs.vmware.com/alliances/2012/04/vmware_vsphere_perf.html

It’s my understanding (although I could be wrong). That installing VMware tools helps with timing synchronisation of the VMware guests so VMware tools should be installed.

Seems EL6 and VMWare is just a big problem. We see it weekly in support and its a non stop issues.