wtf is raid-failure?

Raid-failure is a straightforward web tool that calculates the risk of a disk failing during a RAID rebuild. If you store important data across multiple hard drives in a RAID 5 or RAID 6 setup, a drive dying isn't your only concern. The real danger is whether your remaining drives can survive the intense stress of rebuilding the lost data. This calculator helps you understand that specific risk so you aren't caught off guard by a catastrophic data loss. The tool focuses on something called a URE, or "Unrecoverable Read Error." When a RAID array rebuilds after a drive failure, it has to read every single bit of data on the surviving disks. If even one tiny piece of data can't be read due to a URE, the entire rebuild fails and your data is lost. This web page takes the guesswork out of that scenario by computing the probability of a URE happening while your system is vulnerable. You would use this if you manage a storage server, run a small business network, or are setting up a home NAS (Network Attached Storage) and want to make informed decisions about your data safety. For example, before committing to a RAID 5 setup with large hard drives, you could plug your drive sizes and error rates into the calculator. If the odds of failure are uncomfortably high, you might decide to upgrade to RAID 6 or invest in a proper backup strategy instead of relying solely on redundancy. The project is built as a simple HTML page, meaning you can open and use it directly in any web browser without installing anything or relying on an internet connection. The README is sparse and does not go into detail about the exact mathematical formulas used behind the scenes. However, this is a fork of an original project by another developer, so it serves as a lightweight, accessible iteration of an existing idea for anyone who needs quick answers about their storage reliability.