Bank's data center knocked offline by loud noise

Even though we have SSDs of high capacity, people still use hard disk as they are relatively cheaper and yes Banks too use them. Hard disk drives (HDDs) have moving parts and if a sound is loud enough (sounds are just a vibration in the air, remember) then it might cause the read/write heads of your hard drive to jiggle so much that they end up crashing.
Members of ING Bank found themselves unable to use their debit cards this weekend due to a loud noise caused by a fire extinguisher test knocked out a few dozen hard-drives at the bank's main data center in Bucharest Romania. It's an uncommon, but not unknown phenomenon -- sound causes vibration, and hard-drives hate being jostled.

The data center downtime caused credit card transactions to fail, internet banking to fail, and ATMs to go kaput. Customers expressed their displeasure on Facebook.

The bank was testing an electronics-safe fire suppression system in the main data center, but a pressure discrepancy caused the system to emit a loud noise while expelling inert gas. According to the bank, the sound was measured a over 130dB -- apparently loud enough to knock the HDD's physical components out of alignment.

Solid state drives (SSDs) don't have any moving parts which means that they're not going to care if they suffer a shock or vibration. So folks switch to SSDs.