A fire has broke out the French cloud computing company OVHcloud, which destroyed some servers and forced the temporary shutdown of others, its chairman said on Wednesday.

OVHcloud, which this week started the process for a potential IPO, told clients to activate their disaster recovery plans following the blaze at a data center in Strasbourg, eastern France.

“Fire destroyed SBG2. A part of SBG1 is destroyed. Firefighters are protecting SBG3. No impact SBG4,” founder and Chairman Octave Klaba said on Twitter, referring to different units housing servers.

“We don’t have access to the site. That is why SBG1, SBG3, SBG4 won’t be restarted today,” he added.

The Strasbourg site is one of OVHcloud’s 17 data centers in France, out of 32 globally.

The fire risked disruption for some customers.

The French government holds national data that is open to the public with OVHcloud. A spokeswoman for an inter-ministerial office for digital services told Reuters that teams were investigating the scale of impact. Its website data.gouv.fr appeared to briefly go down.

Founded by Klaba in 1999, OVHcloud is the biggest European-based cloud services provider, competing against U.S. giants Amazon Web Services, Microsoft’s Azure and Google Cloud, which dominate the market.