Learn/SEV1
SEVERITY

Severity 1 (High)

Major incident. Significant functionality is broken or degraded, but a workaround may exist or the impact is partial.

SEV1

Major incident. Significant functionality is broken or degraded, but a workaround may exist or the impact is partial.

"It Hurts, But We Are Alive"

SEV1 (Severity 1) is a major issue. A core feature might be broken (e.g., "Users cannot update their profile pictures"), or performance is severely degraded (e.g., "Page loads take 10 seconds").

SEV1 vs. SEV0

  • SEV0: The house is burning down. (System is down).
  • SEV1: The kitchen is on fire, but the bedroom is fine. (Major feature broken).

Response Expectations

SEV1s require an Incident Commander and usually a Scribe. You should wake people up if it happens at night (depending on your On-Call policy), but you might not wake up the CEO.

ExThe Broken Image Upload

"A social network pushed a bug that prevented all image uploads. Users could still login and chat."

Impact
User engagement dropped 40%.
Resolution
Declared SEV1. Rolled back the change in 45 minutes.

Why SEV1 Matters

Urgent, but the company is not "dead".

Business impact is high, but not existential.

Requires immediate attention but follows standard incident roles.

Common Pitfalls

Severity Inflation
Marking everything as SEV1 makes people ignore alerts ("The Boy Who Cried Wolf").
Severity Deflation
Calling a SEV1 a "SEV2" to avoid waking people up. This hurts customers.
Missing Role Formalities
Running a SEV1 without an assigned IC.

How to Use SEV1

⏱️
SLA: Target response < 15 mins.
📝
Assign Roles: You need an IC and Scribe.
📣
Notify Stakeholders: Keep the business informed.

Frequently Asked Questions

Is performance a SEV1?
Yes, if it significantly impacts usability (e.g., >3s latency for 50% of users).
Do I need a War Room?
Yes. Coordination is still required to prevent it from becoming a SEV0.
Can I go back to sleep?
No. SEV1s must be fixed immediately.

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