Opal4 will be going down this evening at 9PM US Central (2020-04-01 21:00 UTC-5) for emergency maintenance. The total downtime should be less than one hour.
The ongoing issue on opal4 has been high system load caused by two separate types of attacks:
- High Apache RAM usage due to attacks against common targets like Wordpress sites
- High CPU usage by the system firewall under a high volume of SYN packets
We've resolved the first problem by tuning our application firewall rules and by working with a couple of specific site owners that were receiving the brunt of the attacks.
The second problem is part of what we're troubleshooting this evening.
At first glance the SYN packet issue would seem like a common SYN flood attack but other shared servers in our infrastructure receive similar amounts of traffic and don't have any problems mitigating it.
In the past 24 hours we've discovered key differences in Opal4's hardware compared to the other servers, so we're working with our upstream provider to sort that out.
Tonight's downtime is at their request to allow them to perform hardware diagnostics in support of that investigation.