Visa has cited a broken switch as the root cause of payment processing problems on Friday 1 June that saw failed transactions across Europe, according to the Guardian.
Some 5.2m transactions failed during the IT outage. A hardware switch was supposed to turn on a data centre but did not function as intended. In the UK 2.4m transactions were unable to complete while a further 2.8m were disrupted in Europe.
Visa Europe chief executive Charlotte Hogg wrote to the Treasury Select Committee confirming that the problem began at 2.35pm on 1 June and was not rectified in full until 12.45am on Saturday.
Hogg wrote: “The incident was caused by the failure of a switch in one of Visa’s data centres. We understand what hardware malfunctioned (the switch) and the nature of the malfunction (a very rare, partial failure). We not yet understand precisely why the switch failed at the time it did.”
The data centre was intended to work as a back up in the event that Visa’s main system malfunctioned, but in this case the back up also failed.
Hogg said: “We operate two redundant data centres in the UK, meaning that either one can independently handle 100% of the transactions for Visa in Europe.
“In normal circumstances, the systems are synchronised and either centre can take over from the other immediately … in this instance, a component with a switch in our primary data centre suffered a very rare partial failure which prevented the backup switch from activating.”
Nicky Morgan, chair of the Treasury Select Committee, said the committee was satisfied with the responses from Visa and cited the detriment to customers as evidence of the growing reliance on card payment systems.