Getting the best out of Zeus VA and ESX

VMware ESX and Zeus Traffic Manager VA (Zeus Virtual Appliance) are a great combination and to ensure that you get the best out of the product a few tweaks need to be made once the traffic manager has been imported into ESX.

This article assumes that the Zeus VA has been successfully imported into your ESX environment. If you need help importing the VA, see this FAQ.

The first stage in ensuring you get the best performance out of ESX and Zeus is to ensure you use the correct setup:

• Hardware: Use a platform capable of running 64 bit virtual machines, and make sure that support is turned on in the BIOS (called something like "Enable Intel VT support")
• ESX: ESX 4.0 and 3.5 have large networking performance improvements (4.0 is much better even than 3.5).
• ZXTM: Zeus 5.1r2 has support for ESX 4.0, and 4.2r2 has the support for ESX 3.5. Ensure you are using the x86_64 version of the Zeus Appliance.

To ensure maximum performance is achieved, we now need to alter the configuration options of the Virtual Appliance.

Network card settings

VMware ESX 4.0 introduced a vmxnet3 network adapter type, which builds upon the enhanced vmxnet type which was introduced in ESX 3.5. It is recommended that these adaptor types be used in preference to the standard e1000 type to give the best performance.

VMware have not validated the new driver on all guest operating system types so we have to trick it to give us the option:

Open the settings dialogue for the virtual appliance, and go to the Options tab:

Change the Guest Operating System type to Red Hat Enterprise Linux 5 (64-bit). We will change this back later, but this will allow us to select the correct network card types. Ensure you save this setting by clicking OK.

Open the settings dialogue for the virtual appliance, and (after checking they aren't already using vmxnet3) delete all your existing network cards. Then add all the cards again, but ensure you select vmxnet3 as the adapter type when adding them:

If you aren't given the option for vmxnet3 and you are using ESX 4.0, change the OS type to "Ubuntu 64bit".

Once the new network cards are added, save them by clicking OK in the settings dialogue.

It is recommended that the OS type be set to either "Ubuntu 64bit" or "Red Hat Enterprise Linux 5 (64-bit)".

CPU settings

With the exception of SSL performance, more vCPUs doesn't necessarily mean better performance. If you have a quad-core system and give the appliance all 4 cores to run on, then you would assume that it performs better than if you just give it 2 cores to run on. However this is not true, using all 4 cores means that when the ESX service console is running, the guest is blocked.

Our recommendation is to give the appliance 2 vCPUs to run on. This seems to give the best all round performance.

Other settings

The default for the appliance is to have 512 MB of RAM assigned to it, you can easily change this if you need more (e.g. content caching). It might be sensible for a busy site assign1GB of RAM. You should keep an eye on the amount of RAM used and free using SNMP or the Current Activity pages of the Zeus user interface.

If you are using Zeus SW inside your own OS on ESX, you should ensure that you add 'notsc' to the kernel command line (e.g. in grub's menu.lst file). This works around various problems with clock jumps under ESX that can cause problems such as Traffic IP group failures.

Crispin Flowerday [Zeus Dev Team] 02 April 2008 4 comments