When you create a VM (virtual machine) in the eNlight Cloud, the VM will be provisioned with the resources that you have defined in the VM template. However, under some circumstances these resources may not be sufficient for the stable running of your hosting environment. If your eNlight VM begins to run out of resources because of the load that has been placed on it, then if you have the auto-scaling feature enabled, additional resources can be allocated from the Cloud's central pool of resources for the time span that your VM's existing resources are unable to cope. This approach ensures that VMs will never crash because of the load that they are placed under, whilst it is also a cost-effective method,as customers are only billed for the additional resources for the time period that they are attached to the VM.
Auto-scaling as a method of managing resources works best with CPU power and RAM, because these are the two resources that are placed under the most stress when the load on a server increases. However, we also recognize that some customers will have a need to add additional storage to their eNlight VMs. Elastic Storage is an option available with eNlight Cloud which allows customers to add multiple disks to their VMs on the fly, with the option to attach and detach these from virtual environments as required.
With eNlight Cloud, you are only paying for the resources that you are consuming. bodHOST is committed to this USP as it is something not offered by other Cloud hosting providers. By providing the pay-per-consumption model, there will be no unexpected bills at the end of the month. With eNlight Cloud you will only ever be paying for the resources that you are using, even if auto-scaling is deployed on your VM to ensure that it remains stable; you will at all times have full control of the expenditure that is generated using the auto-scaling feature. Furthermore, auto-scaling in eNlight Cloud takes place automatically so there is no need for any manual intervention; resources are automatically provisioned and removed from your VMs without the need for the environments to be rebooted, therefore no downtime will be incurred at any point.
Cache memory can be seen as being an extension to RAM, the primary method of temporary storage used by services and applications. Computers are able to access cache memory and RAM faster than a standard hard disk. When processing data, a computer will first look in the cache memory to see if there are any stores of information from a previous reading; if this data is retrievable then it will be moved over to the RAM.
The Economy-based model is offered with the intention of limiting the amount of cache that is stored in the RAM. The benefit of this model is that the RAM allocations of VMs don't need to be permanently increased, as there is no extra growth to be handled. Rather than reading data from the RAM, it is instead read from the disk. Although the costs are kept to a minimum with this model, the performance of your applications is compromised. This model is best suited to customers with low-traffic websites where performance isn't the number one priority and instead keeping costs low.
With the Performance-based model, eNlight maintains a considerably large cache size. The result of this is the increased performance as it avoids the repetition of the collection of data from the disk drive as future requests can be processed directly from the cache memory. The downside of this model is that VMs can be more expensive to run because they require larger RAM allocations, but the improved response times mean that this investment is worth it for most customers. Customers with high-traffic websites stand to benefit the most from the Performance-based model.