What would we do if Google was hacked and corrupted?
Panic, because that implies the existence of a larger fish than Google with malicious intent. It'd be an organisation more powerful than many (most?) governments effectively declaring war on the world.
Google uses NetApp filers. (Former insider for Netapp)
If some malicious dickwad managed to coordinate simultaneous site accesses, it could be done. Those big filer fleets use hyper redundancy, both with the storage media itself, but also with the controller heads, and with dedicated fiber links to remote Disaster Recovery sites.
It would take some social engineering to pull off, but this is how it could be done:
Arrange technical malfunctions at both the main site, and at the disaster recovery site. (there are any number of ways to do this remotely which I wont discuss in detail). THEN, the attackers pose as NetApp field support techs, and then infiltrate the sites. (Normal policy is to attempt issue recovery with a live telephone call, but if there is physical hardware damage, large customers like Google are entitled to free on-site service and support to resolve the issue.)
Once on site, it would take the attacker approximately 30 seconds to initiate an unrecoverable loss of all data on the filer fleet, by batch-issuing commands to the controllers to go into maintenance mode on the Service Processor interface, and then initiate special boot option 4A.
https://community.netapp.com/t5/ONTAP-Discussions/Boot-Menu-Option-4/td-p/4561Once started, the process cannot be interrupted. Once complete, all data in the filer will be lost.
It aggressively scrubs all disks in the reformat, because it is intended to be used when transferring filers to new owners, and it meets DOD security requirements for "Secure" erasure.
Now then-- This whole plan is probably unworkable for anyone but a state agent. It would require infiltration of the NetApp technical support infrastructure, to successfully intercept the field service calls, and send operatives instead.
But still possible to be accomplished.