99.9% uptime: what that number allows, and what actually breaks

Ranked, near enough, by how often we see them on shared platforms. Application faults come first: a plugin update white-screens WordPress, the site goes dark, and the server beneath it hums away untroubled. Resource exhaustion follows, where your own traffic surge or a neighbouring account runs headlong into PHP process limits. After that, planned work such as kernel patches and PHP upgrades, which when handled properly cost you seconds of graceful restart. Then hardware, disks mostly, which is what RAID and real backups exist for. Then network events: upstream carrier trouble, DDoS weather. Last, and by far the most famous, whole-datacentre incidents.

The order matters because the advertised figure covers only a slice of it. An uptime SLA records whether the server responded, not whether your site worked. The plugin that broke your checkout registers in no one's downtime column. Which is why daily backups and a staging environment do more for the uptime your visitors actually feel than the distance between 99.9% and 99.95% ever will.

Concretely, here is how ours is built. NVMe RAID storage, so one dead disk changes nothing at all. LiteSpeed serving cached pages, which keeps most traffic spikes away from PHP entirely. Per-account resource isolation, so a neighbour having a rough afternoon does not drag you into it. External monitoring running non-stop, wired to alerts that wake a real person. Daily backups with self-service restores, which turns the commonest failure class of the lot, the application kind, from an outage into a ten-minute rollback.

And the limits, stated plainly. We run scheduled maintenance, announced, off-peak and measured in seconds. We depend on upstream networks like every other host. A determined DDoS is weather we absorb and mitigate rather than something we can abolish. We commit to 99.9% on every plan because that is the level we can sustain across thousands of accounts, and we would rather walk you through the number than leave it on the page as decoration.