Connecticut's IT Managed Services Blog

Upgrading your computer

Everyone likes upgrading their PC because it means they can now use a faster computer with more features, but it’s also a great way to save money on electricity costs while going green. As technology advances so does the techniques used to save power. Anyone who had a laptop a decade ago remembers the problems with heat, size and horrible battery life. Nowadays these problems are barely a concern with laptop battery life being at minimal 3-4 hours, but generally can go up to 10 hours or beyond. New breakthroughs in battery technology have helped, but it has been the tech industry as a whole that has increased battery life. As new CPUs and Memory chips are being created, one of the main goals is to make sure the next generation runs faster, but also uses less electricity and generates less heat. This is done through new techniques created to create smaller transistors, which allows more to be placed on a single chip, and less electricity to be needed to use them. This combined with new features that keep energy consumption in mind have allows computers to lower their speeds when idle to decrease and consume less power, but can increase speed again when needed.

Is a server crash not an option for your company? Is having your server up and running the life and soul of your business? Then you may want to consider VMware’s Fault Tolerance (FT) feature. VMware Fault Tolerance is a step up from VMware High Availability (HA), with High Availability being VMware’s backup for a VM crash, if a server running a VM happens to go down then the host reboots on a different host. This allows for only a minute or two of downtime as the Virtual Machine starts up on a new server and the primary host that has crashed is restarted, if possible. This is extremely useful and can keep a business functioning with only a moment of downtime. What Fault Tolerance does is eliminate that couple minutes of downtime so that even if a server crashes, nothing is felt by the user. This feature gives companies that can’t stop functioning, even for a minute, the security they need to run their businesses.

How does FT work? Well with HA there is a primary server who runs the VM and a dedicated secondary host that is there in case of failure, if/when that failure occurs the secondary host is started and the VM is restarted on the new host. The failure is detected by using VMware’s heartbeat function that pings the server every second to ensure it is still active on the network, if the host stops responding it is considered to have failed and the VMs are moved to a new machine.  FT continues this trend, but instead of waiting for a host to fail and then restart it uses vLockstep to keep both hosts in sync that way if one was to fail than the other would continue running without having the user notice the server failure. By sharing a virtualized storage, all the files are accessible to both hosts and the primary host updates the secondary host constantly in order to keep both hosts RAM in sync. FT has a few rules to ensure it works properly:

• Hosts must be in an HA cluster
• Primary and secondary VMs must run on different hosts
• Anti- affinity must be enabled (A configuration that ensures that the VM cannot be started on the same host)
• The VMs must be stored on a shared storage
• Minimum of 2 Gbps Nics, this is to allow vMotion and FT logging
• Additional NICs for VM and management network traffic

VMware HA (High Availability) is a major step in setting up a disaster recovery objective. With HA enabled, each ESXi host checks in on the other hosts and looks for a failure, if a failure should occur the VMs on the failed host are restarted on another server. To enable HA on your network a few prerequisites are required; All VMs and their configuration files must reside on a shared storage, this is required so that all the hosts have access to the VM if the host running it should fail; Each host in a VMware HA cluster must have a host name and a static IP, this will guarantee that each host can monitor each other without having false positives on failure if a host changes IP address; Hosts must be configured to have access to the VM network; Finally VMware recommends a redundant network connection, if a network card should fail this would allow communication to the host it is associated with, without this redundancy the host would seen as failing.