Lightning strike causes Google data centre to lose power Company says only tiny proportion of data stored at Belgium facility affected

Repeated lightning strikes have caused a Google data centre in Belgium to lose a small amount of data after the company was unable to restore some information.

Four successive strikes on the electricity grid that powers facilities in Saint-Ghislain, near Mons, affected 5 per cent of persistent, or non-virtual disks in the zone that powers Google Compute Engine, its cloud computing platform.

The problem was compounded when the data centre's battery backup failed, although Google said the vast majority of the data was recovered between last Thursday, when the strikes occurred, and Monday.

On Friday it said only 0.1 per cent of persistent disk space had been affected, and this was reduced to 0.000001 per cent by Tuesday.

"In almost all cases the data was successfully committed to stable storage, although manual intervention was required in order to restore the systems to their normal serving state," the company said.

"However, in a very few cases, recent writes were unrecoverable, leading to permanent data loss on the Persistent Disk. This outage is wholly Google's responsibility."
Google said it was upgrading its storage hardware so it would be less susceptible to power failures, and that most of its storage is running on this technology.
Google Compute Engine is used by many of the world's biggest companies to run virtual desktops.