At this point, you already know how powerful syslog is. But here’s the thing: Scaling your systems to consume high volume syslog is like fighting zombies. Weird, unexpected behavior and no easy solutions. Before you fight zombies, though, you have to understand them.
So, here are the challenges for scaling syslog one by one:
Why is UDP's fire and forget design a problem?
Network devices send data over UDP and then forget about it. Unlike TCP, UDP never checks whether the destination and port are listening. That matters because you cannot send UDP syslog over long distances. Every network hop makes it more likely you'll drop data, and the sender will never know.
The fix is architectural: locate your syslog servers as close to your UDP data sources as possible. This is the nature of the protocol, and you have to design around it rather than wish it away.
What happens when syslog ignores the RFCs?
Parsing pain, that's what. Two RFCs (RFC 3164 and RFC 5424) describe what syslog should look like and how it should be transmitted to your logging tools. Yet much of what vendors call syslog is not RFC-compliant, which creates parsing and event management headaches downstream.
Don't assume that data labeled "syslog" is actually RFC-compliant syslog; verify your data as you onboard it. Check timestamps, create the right source configurations, and implement event breakers so your tools can consume the data cleanly.
How do you plan for high data volumes?
Plan for the spike, not your daily average. Your typical volume baseline will not stay consistent, and the moment you need your observability platform most is when data volumes go through the roof. When your firewall breaks and starts sending large volumes, or the security team is handling a breach investigation, that is not the time to discover your ceiling.
Work with your business leaders to determine the required level of reliability and the point at which your systems will start to fail. This is a business decision; bring data to support your options and let leadership choose the level of investment they will support. Keep documentation handy for the inevitable finger-pointing if something goes wrong.
Why is securing syslog so hard?
Securing syslog involves tradeoffs. UDP packets cannot be secured with TLS, which makes for an uncomfortable conversation with your security team. TCP syslog supports TLS, but then you run into scaling issues with load balancers and additional overhead that some devices cannot absorb.
A reasonable compensating control is to put your syslog servers close to your syslog sources, then let the receiver handle encryption for the longer journey downstream. You protect the data where it travels farthest without overloading source devices.
How do you scale syslog the right way?
Consuming data, getting it into your logging systems, and not dropping anything along the way is a major challenge in high-volume environments. Skip the planning, and you might create a significant security gap. Keep these four practices in mind.
Work with your system admins to use consistent formats
Talk with your network and storage engineers about implementing standardized data formats. Document the standards your organization will follow and hold teams accountable. Every class of device should have a master logging configuration that everyone agrees to. Audit formats regularly to catch one-offs, and have a process to respond. This is suitable work for overnight teams and a contribution to data governance.
Load balance your traffic for scaling syslog
There is debate over the best technique to load balance syslog. The key question is whether your environment can support the chosen approach. Do not implement an IP multicast load balancer if your network and virtualization teams lack the necessary skills. Implement what you can support today and plan to evolve as teams build skills. Cribl Stream includes a native syslog load balancing feature that fans TCP syslog events across all worker processes on a node, scaling to roughly 100 MB/s of ingested syslog per node, according to Cribl engineering benchmarks (2024). Load balancing syslog challenges many network teams, so be prepared to implement, adjust, and iterate.
Place your syslog receivers as close as possible to your UDP sources
As networks grow, syslog servers often drift far from the sources they serve. Collect data as close to the source as feasible when scaling syslog. By placing a receiver near the source, you can accept UDP locally and forward the data to Splunk or Elastic over reliable TCP. You get the mix of local UDP delivery and dependable transport. If you use Cribl Stream as your syslog pipeline, persistent queuing stores data to the file system if a destination goes down and retransmits it when the destination comes back up.
Use tools to clean up and reduce data
A considerable portion of syslog traffic is not useful syslog but noise from network devices. You need options for cleaning, repairing, enriching, and reducing your data in flight. Cribl Stream provides those options and visual validation so you can confirm data parses as expected before it reaches analytics tools.
How Cribl can help with scaling syslog
As an observability engineer, you need to work with syslog data in a scalable way. Quality data outputs mean operations and security teams get the right data to do their jobs, especially on the worst days. Cribl Stream, part of Cribl's product suite, was built for this problem: receiving high-volume syslog close to the source, protecting it with persistent queuing, and routing it where it needs to go without lock-in or data loss.
Cribl's platform is vendor agnostic; you decide what to collect, how to shape it, and where to send it. Route full-fidelity copies to low-cost storage while sending reduced, enriched events to your SIEM or analytics tools. Fix broken timestamps, normalize inconsistent vendor formats, and drop the junk before it increases your license costs. That is the choice, control, and flexibility that can make syslog manageable.
See how Cribl Stream helps enterprises handle UDP syslog challenges for a deeper look at the syslog capabilities in action.
To get started with scaling syslog, try Cribl Stream and the free Cloud Sandboxes.
Why is scaling syslog so difficult?
Syslog uses UDP, a fire-and-forget protocol with no delivery guarantee. Inconsistent vendor formats, unpredictable volume spikes, and gaps in encryption make syslog hard to scale. These challenges compound in high-volume environments.
Can I send UDP syslog over long distances?
No. Every network hop increases the likelihood of dropped packets, and UDP senders do not know when data is lost. Place your syslog receivers close to your UDP sources, ideally in every data center.
Is all syslog data actually RFC compliant?
No. RFC 3164 and RFC 5424 define syslog formats, but much of what vendors call syslog does not follow those formats. Do not assume compliance. Validate timestamps, formats, and event boundaries when you onboard each source.
How should I size my syslog infrastructure?
Plan for the spike, not the daily average. Your observability platform must handle peaks such as firewall failures or breach investigations. Work with business leaders to set a target resilience level, document the decision, and size your systems to match.
Can syslog traffic be encrypted?
UDP syslog cannot use TLS. TCP syslog supports TLS, but it adds load-balancing complexity and overhead that some devices cannot handle. A practical approach is to place receivers close to sources, then encrypt downstream delivery over TCP with TLS.
How does Cribl Stream help with scaling syslog?
Cribl Stream is a scalable syslog pipeline. It receives UDP close to the source, forwards data over reliable TCP, and uses persistent queuing to hold events on disk if a destination goes down. It can also process and validate syslog data in flight.
