Getting the best out of ZXTM and ESX

VMware ESX and ZXTM VA (ZXTM 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 ZXTM has been imported into ESX.

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

The first stage in ensuring you get the best performance out of ESX and ZXTM 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 3.5 has some large networking performance improvements.
• ZXTM: ZXTM VA 4.2r2 has the required version of vmware-tools for ESX 3.5, and ensure you are using the x86_64 version of ZXTM.

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

Network card settings

VMware ESX 3.5 introduced a new network adapter type, enhanced vmxnet, this has much higher performance and lower overhead than the standard e1000 that was previously used for 64 bit guests. 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 again, and delete all your existing network cards. Then add all the cards again, but ensure you select enhanced vmxnet as the adapter type when adding them:

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

Finally, open the settings dialogue again, and change the Guest Operating System type to Other Linux (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 ZXTM 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 ZXTM VA 2 CPUs to run on. This seems to give the best all round performance.

Other settings

The default for ZXTM VA 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 to give ZXTM VA 1GB of RAM. You should keep an eye on the amount of RAM used and free using SNMP or the Current Activity pages of the ZXTM user interface.

Crispin Flowerday [Zeus Dev Team] 02 April 2008   2 comments