When comparing Fluentd vs Sentry, the Slant community recommends Sentry for most people. In the question“What are the best log management, aggregation & monitoring tools?” Sentry is ranked 2nd while Fluentd is ranked 4th. The most important reason people chose Sentry is:
It's what Sentry calls [Rollups](https://docs.sentry.io/learn/rollups/]. All individual issues rolled-up can still be drilled down. Also two issues can be **merged** manually.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Logs everything in JSON
Gives structure to unstructured logs.
Pro Logs stored to FS buffer while network is down
Logs aren't lost due to network issues.
Pro In-stream processing
With a list of 150+ plugins, Fluentd can perform all kinds of in-stream data processing tasks.
Pro Huge plugin ecosystem
Fluentd has a plugin ecosystem that has resulted in developers creating over 150 plugins for the service.
Pro Prioritizes simplicity and robustness
For example, inputs and outputs have built-in support for buffering, load-balancing, timeouts and retries so to be able to deliver data reliably.
Pro Free and open source
Licensed under Apache 2.0.
Pro Routing based on tags
Pro Exponential retry wait
Pro Copy to multiple storages
Pro Based on CRuby
Pro Consolidates similar errors and makes resolution easy
It's what Sentry calls [Rollups](https://docs.sentry.io/learn/rollups/]. All individual issues rolled-up can still be drilled down. Also two issues can be merged manually.
Pro Email/Slack/GitHub/Hipchat integration
Newly discovered issues (i.e. one that isn't rolled-up under and existing one) can generate an instant notification via many means.
Pro Has an official Docker image
Sentry has an official Docker image which means it's likely going to be well reviewed and maintained for a while and it makes it easy to set up.
Pro Completely open source, with a hosted version available
Sentry is a completely open source tool. It's free to use if you want to run it on your own. If you want to avoid the overhead of running and maintaining another server, it also has a hosted version available at www.getsentry.com
Pro Source maps support
Has support for source maps.
Pro Can create projects and teams
A single Sentry server can be used for various teams/products.
Cons
Con Difficult to setup
Requires a significant time investment to get up and running.
Con Not really a logging solution
Sentry collects exceptions, it's not a solution for log aggregation.
Con Can't filter by browser versions
Sentry only filters by browser names and not by browser versions (for example: Firefox, instead of Firefox 27, Firefox 28 etc...)
Con No free cloud hosting
Unfortunately there is no free plan for cloud hosted solution. Only self-hosted solutions are free to use.