How do I benchmark a VPS?

Disk is where providers differ most and where synthetic marketing numbers are least useful. Test 4K random IOPS with a queue depth of 1, which is what a database actually does, rather than sequential throughput, which looks impressive and predicts nothing.

Watch steal time throughout the run. A benchmark that looks good at 03:00 and poor at 20:00 is telling you about your neighbours rather than about the hardware.

• sysbench cpu --cpu-max-prime=20000 run — single-thread performance
• fio --name=rand --rw=randrw --bs=4k --iodepth=1 --size=1G --runtime=60
• iperf3 -c a-known-endpoint — real throughput, not the advertised port speed
• vmstat 1 during all of it — watch the st column