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Overview

Hardware issues can sometimes (rarely) occur, where something is not working right and our monitoring systems may not have picked up on it. This could potentially be non-satisfactory CPU performance, disk performance, or other such issues with the server hardware itself. There are various ways you can diagnose this and provide information to our support team. As always, please open a ticket if you run into any problems.

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CPU Performance

If you are experiencing non-satisfactory CPU performance on a virtual server, there are a few things that you can check. You can try running the top command in your operating system and checking the value called st. This indicates CPU steal, which is the percentage of CPU that your VPS is waiting for from the hypervisor.

Generally, we try to keep our hypervisors at 0% CPU steal values. However, in some rarer cases where VPS hypervisors have higher CPU contention, you may see up to 5-10% CPU steal. This is not abnormal, especially in a shared environment where there are other virtual servers that have to compete for CPU resources. Even if there is some CPU left at the hypervisor level, some CPU steal could still present itself when the host node is past 50% CPU usage and starting to use hyperthreading (vCPU), or could present itself due to other parameters.

If you are seeing CPU steal values increase past 10%, it may be good to open a support ticket. You can also use monitors such as HetrixTools or Netdata to monitor the CPU steal values without having to constantly run top. Using these tools and providing our support with graphs can help us determine if the CPU steal is problematic and when it is specifically occuring.

If you are not seeing any CPU steal and CPU performance is unsatisfactory, please open a ticket and we will see what we can do or if there is anything we can diagnose. It is also important to note that Geekbench tests may show lower performance if your VPS is starting to use hyperthreaded vCPU cores.

Note: CPU steal values do not exist on bare metal hardware and/or dedicated servers. If you are experiencing unsatisfactory performance on a dedicated server, you could try running lm-sensors (install lm-sensors first) and checking the CPU temperatures.

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Disk Performance

Generally we use enterprise Gen3 or Gen4 NVMe SSD’s across almost all of our VPS hypervisors, so disk performance issues are extraordinarily rare. We would recommend running curl -sL yabs.sh | bash -s -- -i -g -n and checking the fio results it outputs (Note: yabs.sh is a third-party tool, use at your own risk). As long as the 1m result is above 1 GB/s and 4k results are above 100 MB/s, it should be okay. Keep in mind that the disk speeds are usually shared, and sometimes Linux caches the disk into memory which causes fio results to be high for 4k/1m. Our virtual servers typically greatly exceed the 100 MB/s 4k and 1 GB/s 1m.

fio Disk Speed Tests (Mixed R/W 50/50):
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Block Size | 4k            (IOPS) | 64k           (IOPS)
  ------   | ---            ----  | ----           ----
Read       | 219.67 MB/s  (54.9k) | 1.64 GB/s    (25.7k)
Write      | 220.25 MB/s  (55.0k) | 1.65 GB/s    (25.8k)
Total      | 439.93 MB/s (109.9k) | 3.30 GB/s    (51.5k)
           |                      |
Block Size | 512k          (IOPS) | 1m            (IOPS)
  ------   | ---            ----  | ----           ----
Read       | 4.30 GB/s     (8.4k) | 4.91 GB/s     (4.7k)
Write      | 4.53 GB/s     (8.8k) | 5.24 GB/s     (5.1k)
Total      | 8.84 GB/s    (17.2k) | 10.15 GB/s    (9.9k)

If you are seeing low disk performance (i.e. under 1 GB/s on 1m or 100 MB/s on 4k), please open a ticket so that we can investigate.