VM /ETC

Posts Tagged ‘networking’

VI3 Enterprise features VMotion, DRS, and HA require identical virtual networking settings on all of your ESX hosts. Unfortunately, VirtualCenter does not apply a central configuration policy or inheritance of settings from the cluster. Maybe a future version of VirtualCenter will evolve to include global configuration abilities? Until such a version is created, each ESX server’s virtual networking settings will continue to be configured individually by most administrators. However, there are some time saving, global configuration options available today. This post summarizes two methods provided by the virtualization community for creating PortGroups simultaneously across multiple ESX hosts. Read the rest of this entry »

A common issue after installing ESX servers that do not have all their NICs cabled is that you can not ping the host. For example, say you have an ESX host with 6 1GB network cards – 2 on board and 4 PCI. You would think that cabling the 2 on board cards would cover network connectivity. Unfortunately the order that ESX recognizes the NICs is not determined in a logical, expected order such as on board and then PCI cards. In fact, if you know how ESX determines how to order the network cards please comment and let us all know! In the meantime, here is how to use a few esxcfg- Console commands to make sure the cabled NICs are linked to the vSwitch that has the Service Console PortGroup (where the ip address is assigned).

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Up until ESX version 3.5 you had to modify various config files to configure ESX NTP time sync. This process was previously automated by the set_ntp.sh script, but now it is even easier because the VI Client can now configure the necessary NTP settings for the ESX host natively. Read the rest of this entry »

if you just need to change an ESX server’s DNS servers, default gateway, or hostname you can use the VI client to make the changes. This might be a rare scenario, but it happens every once in a while.

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Why is it that migrating to virtual infrastructure (VI) is most often considered to be the responsibility of the server administrators? Anyone who has already done it can tell you it involves much more than servers and hardware. Even for small companies, virtualizing servers potentially (and usually) involves networking, storage, security, and infrastructure services changes. In fact, it is often as involved and complex as moving your physical servers from one data center to another.

So why is there a perception that implementing VI is only a server team responsibility? Obviously, one reason is because on the surface it’s about installing and consolidating operating systems on server hardware. Another reason is because VMware, the source for all the interest in migrating to VI to date, has done such a great job marketing their products as just server installs. Read the rest of this entry »

I get asked this all the time. “How many NICs does ESX need? 2, 4, 6 or more?”

Well, it’s not really about how many NICs ESX needs. I’m not recommending it, but the fact of the matter is that VI3 really only needs 1 NIC per ESX host. It’s just smarter for a company to build some redundancy and load balancing into their VI design. So, let’s say then that ESX just needs 2 NICs minimum.

The real question is “How many NICs does your network infrastructure and VI performance require?” Do you have or will you have: Read the rest of this entry »

Too many companies try to implement replication to a DR VI without upgrading the bandwidth between the primary and secondary sites. Let’s look at a simple example that can illustrate what could go wrong with inadequate bandwidth.

A company has 5 VMs that each use 20 GB virtual disks. The data is not too dynamic and data change only averages about 1o% per business day or roughly 1 GB per hr. This data change could be common activity like Active Directory replication, files saved to user home folders, application databases, and email. This is common to a small to medium sized business.

Using the Data Replication Minimum Bandwidth Requirements chart provided by NSI, makers of Double-Take, You can see that the 100 GB falls into the LAN 10Mb/s bandwidth category (in the 10% column). Click the thumbnail image to the left for a better view of the chart. We’ve already proved that this company needs better than a T1, but it’s close enough not to convince those that think their data change will be lower than 10%.

The real “gotcha” is that companies never consider how long it will take to replicate the data. Read the rest of this entry »