Yandex Cloud says 2.84% of customer data is gone for good after drone strikes

The numbers are simple. More than 97% of affected customer data came back, and 2.84% did not.

Yandex says recovery of that last slice is impossible. The cause, in its words, is critical damage to equipment and no backup copies on the platform.

Why it matters: the loss was not random. Customers who had already switched on backup tools lost nothing, because their information stayed fully preserved.

It is unclear what "on the platform" means exactly. It could mean Yandex keeps no backups of its own cloud, that its resilience methods do not create multiple copies, or that some clients did not protect their data. Yandex has not spelled it out.

Three Yandex facilities were hit in four days. Here is the order of events:

• October 8, Sasovo (Ryazan region): a fire shut the site down. It has a declared capacity of 12 megawatts and hosts two of the three supercomputers used to develop Yandex's AI model.
• October 9, Kaluga region: one of the company's largest data centers, designed for more than 3,800 server racks and about 63 megawatts, was partly put out of action.
• October 11, Vladimir: a large complex of around 56 megawatts stopped operating completely.

No injuries were reported at the sites. The attacks were attributed to Ukrainian forces, and Ukrainian President Volodymyr Zelenskyy said after the first strike: "We always respond in mirror-like fashion."

He added that Russia has been hitting Ukrainian data centers and that Ukraine is responding. Russia has struck several Ukrainian data centers and telecom sites over the past month.

Big. The Vladimir strike alone reportedly disrupted more than 80 Yandex Cloud services, including computing, databases, storage and AI tools such as the YandexGPT API, which is the connection other programs use to call Yandex's AI model.

Consumer services felt it too. The Alice voice assistant, Yandex Music, Telemost video calls and Yandex Smart Home were affected.

Vladimir's regional governor said the drones also hit infrastructure outside the city. That started a fire and took two electrical substations offline, leaving about 5,000 residents without power.

Yandex is often called "Russia's Google". It runs search, maps, ride-hailing, delivery, streaming, email and cloud services, and much of the country's internet infrastructure relies on it.

In real life Imagine your photos live on one hard drive in one building, and you never made a second copy. If that building burns, the drive is gone no matter how good the company that owns it is. That is the gap between "the cloud" and "a backup."

During the crisis, Yandex's status page was blunt. "We consider the remaining resource configuration to be unstable," one update read.

It also said the platform was in emergency mode and recommended "using any other alternative disaster recovery plans." Technical support channels, it warned, could be unstable too.

Yandex said its teams were working around the clock to keep services running and to help affected customers and partners.

Even so, it could not give a reliable restoration timeline, and it urged customers to rely on alternative infrastructure for disaster recovery in the meantime.

Sasovo and Vladimir had stopped operating completely, while Kaluga ran in a degraded state. Its own console, API, IAM, container registry, databases, S3 storage and Kubernetes were available with some issues, while compute, AI Studio and security services were only partly available.

One customer reported broken downloads of files from Yandex Disk, with HTTP 302, 504 and 500 errors. At that point it was unclear whether anything had been irreversibly lost.

The first fire hit Yandex's ru-central1-b availability zone in early October, and later strikes disrupted more of its cloud and payment services. Ukrainian press said the attack was ordered by Kyiv.

Sasovo is described as one of Yandex's five large data centers, with tens of thousands of servers. The supercomputers there matter because they are used to develop the company's AI model.

The Vladimir site is part of one of Yandex's largest data center complexes. In March 2026 the company commissioned an additional data center there, built for 2,800 server racks and 40 megawatts.

Network monitor NetBlocks saw a sharp drop in Yandex and Yandex Cloud connectivity across Russia between October 8 and 11. That matches what customers described: files that would not open and services that timed out.

Russia and Ukraine have both escalated attacks on each other's technology infrastructure. Data centers, once the quiet part of the internet, are now part of the story.

The big picture: a cloud provider's promise is that hardware failure does not become your problem. Here, a physical attack on the hardware showed which customers had made their own copies.

Yandex is changing how new virtual machines are set up. This is the main fix:

• Backups on by default: automatic backups will be enabled whenever a customer creates a new virtual machine in Yandex Cloud.
• Opt-out stays: users can still turn the feature off in the management console.
• More resources used: unless customers opt out, backups will consume, and be billed for, extra storage.
• A new zone: Yandex launched availability zone ru-central1-f on Wednesday, in what it calls a "new location," separate from the others.

The company has not said where the new zone is. It has set quotas on how much customers can use there, and it cannot yet handle traffic to private endpoints.

The catch: many countries restrict technology sales to Russia, so adding hardware quickly is harder than for most cloud providers. Quotas on a new zone fit that picture, though Yandex has not given a reason.

Partly. Yandex's recovery announcement links to a page about the benefits of a hybrid cloud for data protection. That page mentions Stackland, Yandex's own product that brings its stack to a customer's own servers.

Three damaged locations and a continuing war give customers a reason to think about where their data sits. Yandex is nudging them toward keeping some of it on-premises, next to the cloud copy.

• If you use a cloud: check that backups are on, and that at least one copy lives in a different location than the live data.
• If you run virtual machines: read the default settings. Yandex's new default is the kind of setting most people never open.
• If you are a Yandex customer: expect backups to appear on new VMs, and check the bill.