How to read a VPS spec sheet without getting fooled

Two providers advertise "4 vCPU, 8 GB RAM, 160 GB SSD" at prices four times apart. Both are telling the truth. The specification is simply not describing what you think it describes.

Seven things to check, roughly in order of how much money they cost you.

1. vCPU: dedicated share or oversubscribed?

A vCPU is a scheduling entity, not an amount of compute. The question is how many vCPUs the provider sells per physical thread. Ratios in this market run from 1:1 to 10:1, and the specification never says which.

How to check: after deployment, run top and look at the st (steal) figure — the percentage of time your vCPU was ready to run but the hypervisor gave the physical core to someone else. Under 1% is a healthy node. Above 5% under normal load means you are sharing heavily. Test during a weekday evening, not at 4 a.m.

vmstat 1 10   # the 'st' column
# or
mpstat -P ALL 1 5

2. "SSD" covers a 30× range

SATA SSD, SATA in RAID, NVMe, and NVMe in RAID-10 all get called "SSD". Random 4K read performance across that range spans roughly 15,000 to 500,000 IOPS.

fio --name=rand --ioengine=libaio --rw=randread \
    --bs=4k --numjobs=4 --size=1G --runtime=30 \
    --time_based --group_reporting --direct=1

If a provider will not say "NVMe" explicitly, assume SATA. If they will not say what the RAID level is, assume there is none — which also tells you what happens when a drive fails.

3. "Unlimited" bandwidth is a port speed with a footnote

Nobody sells unlimited transfer, because transit is metered upstream and someone pays for it. What "unlimited" means in practice is one of:

• A fair-use clause that kicks in at an undisclosed threshold
• A slow port — 100 Mbps "unlimited" is 32 TB per month at absolute maximum
• A soft cap enforced by an email asking you to reduce usage

An explicit allowance is more honest and easier to plan around. Ours run 2 TB to 30 TB by plan, and exceeding it throttles the port rather than generating an invoice — stated plainly rather than in a clause.

4. Overage billing is where surprise invoices come from

Ask directly: what happens at 101% of the allowance? Three possible answers, and they differ by orders of magnitude in cost.

• Throttle. Port drops to a lower speed for the rest of the month. Annoying, free, predictable.
• Overage billing. Typically $1–$10 per TB. A misconfigured backup job or a modest DDoS can produce a four-figure invoice.
• Suspension. Rare, and worse than either.

5. KVM or a container?

"VPS" is used for both full virtualisation (KVM, Xen HVM) and shared-kernel containers (OpenVZ, LXC, Virtuozzo). They are very different products at similar prices.

Containers share the host kernel. You cannot load kernel modules, run nested virtualisation, use certain WireGuard configurations, or boot a custom kernel. Memory reporting is often misleading. On the other hand they are cheap.

systemd-detect-virt     # kvm, lxc, openvz, none
lscpu | grep Hypervisor

6. Where is it, really?

"Europe" is not a location. Ask which city and which facility. A provider that will not name the datacenter is reselling, which matters because the actual host's abuse policy is what governs you, not the reseller's marketing.

Check bgp.tools or whois on the IP: if the netblock belongs to a different company than the one you are buying from, you are buying from a reseller. That is not automatically bad — plenty of good resellers exist — but you should know.

7. What is not in the price?

The advertised figure is frequently not the invoice. Common additions: setup fees, per-IP charges, DDoS protection as a paid tier, backups, control panel licences, and an "unmetered" surcharge. Reconstruct the total for a realistic configuration before comparing anything.

A checklist you can paste into a ticket

1. What is your vCPU-to-physical-thread ratio?
2. Is storage NVMe or SATA, and what RAID level?
3. What is the exact monthly transfer allowance, and what happens at 101%?
4. KVM or container?
5. Which city and which datacenter?
6. Do you own the IP space, or is it upstream?
7. What is the total monthly cost including every mandatory fee?

A provider that answers all seven directly is a provider worth considering. One that deflects on three has told you something useful anyway.