This is one of the times when the hardware spreadsheet will show its true usefulness. So, as long as we have been keeping track of our counts through each section, this segment of server selection will be much simpler. By this point, our spreadsheet should look something like this:

We don't care about the total cost for each part yet. It might be a good idea to create a separate tab or copy of the spreadsheet for each vendor we want to consider. This way, we can comparison shop. Also remember that the counts are inflated by at least one replacement in case of failure. So we want to look for two 10-core CPUs, eight 16 GB memory modules, and so on.

Now it's time to do some research. Follow these steps:

While this is straightforward, it requires a lot of time. The amount of server variants available, even from a single vendor, can be staggering. This is one of the reasons we only consider 1U and 2U servers. The other is that 4U servers and larger are often designed for much different use patterns related to vertical scaling, incorporating more CPUs, hard drives, and even multiple concurrent motherboards.

For our purposes, that is simply too powerful. When purchasing servers with the explicit intention to obtain multiple, redundant, and compatible examples, this becomes more difficult as the cost and complexity of the servers increase.

Although we have reduced our sample size, there is still more work to do. When considering the compatible CPUs, if we want 10-core chips, and the motherboard only supports up to 8-core chips, we can remove that from consideration. This also applies to available memory slots and sizes. Yet there's an unwritten element to RAM: maximum amount. If the motherboard only supports up to 384 GB, and our earlier calculations show we may eventually want 512 GB, we can immediately cross it off our list.

Since RAID and network cards must be plugged directly into the motherboard or an expansion daughter card, it's the amount of these available slots that directly concerns us. We need at least two for both cards that should drastically reduce the size of our list, especially in the case of 1U servers.

While doing this compatibility verification, it is difficult to ignore prices listed next to each choice, or the total price changing with each selection. We might as well take advantage of that and fill in the rest of the spreadsheet, and make a copy for each vendor or configuration. Some overall choices are likely to be better complete matches, or offer better future expandability, or better price points, so tracking all of this is beneficial.

RAID controllers and network interfaces are somewhat special cases. Some servers, in order to reduce size, integrate these directly into the motherboard. This is especially true when it comes to network modules. If at all possible, try to resist integrated components.

If these fail, the entire server will require replacement. This makes it much more difficult and expensive to fulfill our redundancy requirement. Server-class motherboards without integrated network interfaces are rare, but we can use these as our backup path if their minimum speed matches what we've configured.

For instance, if we want a 10 GbE card, and the motherboard has integrated a 10 GbE module, we can reduce the amount of excess cards on our spreadsheet by one. It's very likely the integrated version is of lower quality, but it can suffice until the bad card is replaced.

Redundancy doesn't have to be expensive.

Here is a list of well-known server vendors that we could consider while completing this section: