How Quickly Does Your Team Recover From Issues

Calculating Mean Time To Recovery

Est Reading Time: 5 min

Devon Bleibtrey

May 12, 2020

Who do you let merge changes into production? Are you confident enough to allow someone new add changes on their first day joining the project? Does it depend on who the individual is? Getting to the level of confidence in your developer operations where you will let anyone on the team make modifications to production is a long journey. It requires periodic backups of data, versioned rollback capability, and a stack of other tools and processes that will let you recover quickly when a change creates an issue. Being able to recover from problems effectively is a key measure of the health of your developer operations.

Identify Incident

To track your team's ability to recover from an issue requires a few metrics. First of which is how quickly you can identify the bug after it makes it into production. Any issues you're able to resolve before that are better measured by your change failure rate, which measures how many issues make it into production to begin with.

How long it takes you to identify an issue impacts how many customers are affected by the issue. To identify problems quickly, you'll want to have a mix of human and automated monitoring solutions in place that you can gather initial timestamps from that indicate when the team found the issue. I'd recommend having a minimum of two systems in place, one being customer support and another being an application performance monitoring (APM) tool.

Customer support can be as simple as a contact form on your website, a customer accessible issue collector on GitHub, or the ability to direct message you on Twitter. Having multiple ways to contact you has its strengths and weaknesses and can create headaches for tracking down when the team first heard of the incident, so you'll want to weigh what makes the most sense for your organization.

There are a slew of tools out there that you can use to catch production incidents before customers realize they exist. Using an APM, like Sentry.io, ensures that when an unhandled exception occurs, you're informed of the problem and have the context to be able to start fixing it. Some are more feature-rich than others, and adding a monitoring platform that can also monitor your data stores, the third party systems you rely on, and security threats like DataDog are worth taking for a test run.

If you already have monitoring tools in place, I'd recommend looking at the chaos engineering tools out there like Gremlin to produce unexpected situations before customers or force majeure create them. Most of the logging tools out there are easy enough to integrate, have some concept of a free plan to get started, and are worth allocating budget towards once you validate they fit your team's needs.

The problem with both of these systems is that they create a lot of noise. There's a non-trivial amount of overhead associated with linking bug tickets to the initial incident reports, determining which incident notification identified the issue first and whether there was an incident report for the problem. Then there's additional overhead associated with rolling code changes up to a specific bug ticket, and one patch may or may not resolve the identified issue. This overhead balloons as bikeshedding ensues figuring out whether the original issue ticket should be reopened based on the regression or if a new issue ticket should replace it.

Avoid wandering into that nightmare until you have a more maintainable way of getting an approximation of what your mean time to recovery (MTTR) is. Two items are less accurate but much easier to monitor and track. One is when reversions or rollbacks occur. The other is taking the timestamp of the first commit made that is working towards getting a hotfix into production. These two values won't give you a holistic view but will get you 80% of what you need to figure out when your team first identified the issue. For the other 20% of cases, you can create a manual log of when you first identified the issue, and when you resolved it. After you have that baseline then you can determine if it's worth your time to pursue optimizing the accuracy of when the team first identifies incidents, programmatically.

Recovery

Once your team has identified an incident, how long does it take you to recover from it? Determining when your team resolved an issue has similar challenges as pinpointing when they recognized the event. Avoid the complications if you're just getting started with measuring MTTR. Use the timestamp of when a reversion or rollback completed if no development was necessary. If development is required to fix the problem, use the timestamp associated with the hotfix rolling out to production as the marker for the issue resolution.

Release Zero

Once you're able to measure how quickly you identify issues and recover from them, you'll need a way to figure out which release introduced the issue into production. Finding the version can be as simple as looking at the latest production release, but if you're deploying tens or hundreds of releases a day more than likely, you'll need to do some investigative work to determine which release introduced the issue. Whether it's cross-referencing APM identified code snippets with releases or looking through release notes to see which versions affected the impacted system, you'll need to figure out what time the release that caused the issue merged into production.

Calculating Mean Time To Recovery

Once you have these three measurements, we can calculate your MTTR and one of the key contributors to it, mean time to incident identification.

Using Django you could implement the function to calculate mean time to recovery and mean time to incident identification like this:

from datetime import timedelta
from django.db import models

class Incident(models.Model):
    time_of_identification = models.DateTimeField()
    time_of_recovery = models.DateTimeField()
    time_of_release_zero = models.DateTimeField()

def mean_time_to_recovery():
    downtime = timedelta(0)
    all_incidents = Incident.objects.all()

    for incident in :
        downtime += incident.time_of_recovery - incident.time_of_release_zero

    return downtime / all_incidents.count()

def mean_time_to_identification():
    downtime = timedelta(0)
    all_incidents = Incident.objects.all()

    for incident in :
        response_time += incident.time_of_recovery - incident.time_of_identification

    return response_time / all_incidents.count()

These are naive approaches to taking a baseline but should give you a figure to start working with. Once you have incidents tracked, you can improve the benchmarks based on your specific needs.

Leaderboard Standings

If you're wondering how your team stacks up against others when it comes to recovering from issues, according to the State of DevOps 2019, 20% of teams are elite performers, 23% are high performers, 44% are medium performers, and 12% are low performers (less than 100% due to rounding). These percentages are based on their performance in all 4 key metrics of DevOps performance.

Regarding ability to recover from an incident here's how other teams are staking up:

Tier Time to restore service
Elite Less than one hour
High Less than one day
Medium Less than one day
Low Between one week and one month

If you'd like the complete breakdown or the methods of the study, check it out in Google's State of DevOps 2019.

Conclusion

Now that you can take a baseline of your mean time to recovery and mean time to incident identification, you can see how new tools and processes you introduce impact these key measurements. Depending on your team, you might have enough incidents occurring that you can use your them to perform benchmarks. If you don't have many incidents, then I would recommend developing a strategy to inject incidents into the system periodically to help identify areas that can be improved and to avoid getting caught flat-footed when an incident happens next.

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