Comment by chippiewill
3 years ago
> Double disk failure is improbable but not impossible.
It's actually surprisingly common for failover hardware to fail shortly after the primary hardware. It's normally been exposed to similar conditions to what killed the primary and the strain of failing over pushes it over the edge.
Isn't that more for load balancing than failover?
For load balancing I would consider this very likely because both are equally loaded. But "failover" I would usually consider a scenario where a second server is purely in wait for the primary to fail, in which case it would be virtually unused. Like an active/passive scenario as someone mentioned below.
But perhaps I got my terminology mixed up. I'm not working with servers so much anymore.
If it's active/active failover then they get the same wear, if it's active/passive most of the components don't, but the storage might. Then again if it's active/passive, flaws can "hibernate" and get triggered exactly when failing over.
You know how they say to always test your backups? Always test your failover too.