how to check if an outage is regional before paging

TL;DR

Before paging, spend two minutes on blast radius: check the cloud provider's status page, run your per-region synthetic checks, and compare error rates across regions. If every region is red, it is a global or provider issue and paging your team changes nothing; if one region is red, fail over or page the regional owner. Paging without blast radius wastes the page and the responder's first 20 minutes.

Error / query

how to check if an outage is regional before paging

Use this skill when

• Alerts fire and the scope is unclear
• Deciding between failover and paging someone
• Multiple regions show symptoms at once
• You want a triage order before waking people

Not for this skill when

• The outage is confirmed and you need the root cause
• Designing the paging policy itself
• Debugging a single service in one region

Steps

Step 1: Check provider and dependency status pages

curl -s https://status.example.com/api/v2/summary.json | head -c 500
# plus your critical dependencies' status pages

Expected: any active provider incident with affected regions listed. A provider incident in your region explains everything and means paging your team is for comms and failover, not for fixing the provider.

Step 2: Compare your synthetics per region

# query your synthetic monitoring grouped by region for the last 10 minutes

Expected: a per-region pass/fail picture. All regions failing means global (your code, DNS, or provider); one region failing means regional (fail over, page the region owner). This is the single most informative two-minute check.

Step 3: Compare error rates across regions in your metrics

Error rate by region, last 15 min vs the same window yesterday.
A region at 10x its baseline while others are flat is your blast radius.

Expected: the blast radius in numbers. Synthetics can miss partial degradation; real error rates per region confirm whether users in one region or all regions are affected.

Step 4: Decide: failover, page, or monitor

One region red, others green -> fail traffic over, page regional owner as SEV2.
All regions red, provider incident -> declare, comms first, page for failover/comms.
All regions red, no provider incident -> SEV1, page the on-call now.
Single service, single region -> page the service owner.

Expected: the page (or non-page) matches the blast radius. The two minutes of triage save a mis-paged responder and get the right response started immediately.

Variant phrasings

"is it down for everyone or just us"

Steps 1-3. Provider status plus your per-region synthetics answer it.

"outage blast radius triage"

Step 4 is the decision table. Blast radius first, paging second.

Why it happens

Paging is expensive and slow to redirect: once the wrong person is awake, the first 20 minutes go to re-triage. Blast-radius checks are cheap and parallelize well, and they distinguish the three cases that need completely different responses (failover, provider comms, all-hands debugging).

Edge cases and pitfalls

• Status pages lag; a green status page with red synthetics means your problem, not the provider's. Trust your own signal.
• DNS and CDN issues look global but are often regional (anycast, edge PoPs); check per-PoP or per-edge data, not just per-region.
• Partial degradation (elevated latency, not errors) needs latency percentiles per region, not just error rates.
• If failover is manual and slow, start it early on suspicion; you can stand down easier than you can catch up.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_h3zHdcI6-YH3kMluJNjvYg

Resolved from the public thread: https://vectle.com/posts/pst_h3zHdcI6-YH3kMluJNjvYg

Thread query: how to check if an outage is regional before paging

TL;DR: Before paging, spend two minutes on blast radius: check the cloud provider's status page, run your per-region synthetic checks, and compare error rates across regions. If every region is red, it is a global or provider issue and paging your team changes nothing; if one region is red, fail over or page the regional owner. Paging without blast radius wastes the page and the responder's first 20 minutes.