How to Choose the Right Service Provider and Service for Server Hosting - Part II

In the previous part of our blog post, we focused on general aspects to consider when choosing a server hosting service provider. In this part, we will focus on one of the most important aspects of the service, which has many misconceptions and varied interpretations in the market. This aspect is ELECTRICITY. 

How to Measure the Power Consumption of Equipment? 

How can you know the power consumption in amperes of the equipment that needs to be hosted? The power of the equipment is usually stated in watts (W). 

First, you should avoid the common mistake of relying on the nominal value of the device's power supply. The nominal value can never be achieved because, at that level, the device would simply stop working. There would be no more power, and the power supply would stop functioning. The nominal value of 1000W is for a server if you add the maximum number of processors, GPUs, hard drives, memory, etc. For example, the nominal value of the power supply in WaveCom's powerful VMware GPU servers is 1200W, but the actual consumption is on average 290W. 

The actual consumption can be most easily obtained from the HPE ILO or Dell iDRAC interface. An even smarter way is to use monitoring software that collects information from all servers and displays it in one place. Commercial systems also provide aggregated reports, showing the average, maximum, and minimum power consumption of a group of devices. The result is usually presented in watts (W) or kilowatts (kW). 

Those using smart power strips can get the same information from them. Depending on the power strip, the client can see their consumption either for the whole strip or even per socket. 

Additionally, our smart power strips allow all power sockets to be switched on and off individually. This is an indispensable feature if a device stops responding and the only way to restore functionality is to remove the device from the power network. For example, there have been cases where switching the power off and on again was the only way to access a misconfigured network device. 

By choosing WaveCom's service, you get access to all information about power consumption in our self-service portal. Always! 

How is Power Consumption Priced - Nominal Value of the Fuse vs. Actual Consumption 

One of the most important but often most confusing questions is the power consumption of servers and its pricing. To make the right choices, it is crucial to know the actual power consumption of your server park. 

In general, service providers price power consumption in three ways.  

1. According to the nominal value of the fuse in amperes (symbol A or abbreviation amp).  

An ampere is a unit of current that indicates how much electric charge passes through the fuse per second.  

In everyday life, electric current can be compared to water flow - how much water flows through a hose in one second.  

For example, if a server cabinet has a commonly used 16-amp fuse, it can allow a maximum of 16 amps of current to pass through it per second. If the consumption exceeds the 16-amp limit, the fuse will switch off.  

To draw a parallel, many houses have 25-amp main fuses. If you turn on the electric heating, stove, oven, dishwasher, and electric car charger all at once, there will be a click and the house will go dark. 

When choosing the main fuse for a house, we always choose it with a margin. The same should be done in the server cabinet. That is, the fuse should always be at least 20% more powerful than our actual power consumption. In homes, we can afford a more powerful fuse because we are billed for actual power consumption. However, in many data centers, you pay according to the nominal value of the fuse. As if you were consuming the maximum possible power from that fuse 24/7. But you never actually do. So, you always pay for power you don't actually use.  

2. In kilowatts, but not according to average consumption, rather in large steps of 1, 1.5, or 2 KW  

A similar story applies when paying for power in kilowatt steps. You need to be very good at predicting your power usage, and you will likely still end up paying for power you haven't actually consumed. 

3. According to actual average power consumption in amperes. 

In WaveCom's server cabinet, however, you pay for the power actually used. Installing a separate electricity meter for each client is not practical. Instead, we monitor the monthly average consumption using smart power strips. Specifically, consumption is measured every five minutes, and the electricity bill is based on the monthly average consumption. 

Therefore, by using pricing based on actual consumption, you achieve significant monthly savings on electricity.  

Service Stability and Fault Tolerance 

In the first part of the blog post, we also mentioned service stability in addition to price. What did we mean by that? 

Let's compare fuse nominal value-based pricing with actual average consumption. You have to choose a fuse for the nominal value. Usually, the options are steps like 6, 10, 13, 16, 20, 22, 25, 28, 32 amps. 

Let's assume you chose a 16-amp fuse. As mentioned earlier, the fuse should be chosen with at least a 20% margin. But in reality, even that margin might not be enough. For example, in a situation where all servers start up simultaneously. Servers consume significantly more power at startup (power surge) than in normal operation. This situation can occur if there has been a complete power outage in the data center due to an accident. When power is restored, all servers start up simultaneously and trip the fuse. 

Complete power outages are, of course, very rare. A more realistic scenario is a backup solution where servers are idle most of the time. Now, however, VMware Power DRS turns on 10 servers simultaneously. Click, and darkness. 

A much more common scenario is when, for some reason, one leg in the cabinet fails. For example, due to a UPS failure. But the service user has misjudged their consumption. For example, they have ordered two 16-amp redundant power supplies, which are usually split between two legs. But more servers have been added in the meantime. Power consumption has reached at least 16 amps or even more. If one leg fails now, it's click and darkness for the client again. 

This again highlights the significant advantage of pricing based on actual power consumption. All the fuses used by all clients are significantly more powerful. There is no need for smaller fuses because billing is based on actual consumption. For example, at WaveCom, the client has 2 x 32 amp fuses available on both legs. This means that the entire cabinet uses four different fuses connected to two different UPS units. If you now connect the server power supply to all four fuses, multiple redundancy is ensured. Therefore, all the aforementioned scary scenarios can be forgotten, and a much more stable and fault-tolerant service is ensured. 

In conclusion, as described above, "the devil is in the details," and there are many different aspects to consider regarding the service provider's power pricing. Especially since electricity can ultimately make up a significant part of the overall service cost. The electricity cost for the same server park can vary up to 2x depending on the service provider. 

In the next and final part of our blog post, we will focus on another very important aspect of choosing a service provider that should definitely be considered for service quality and operational continuity - the network services of the data center.