Hi Thamanna, Ceph's built to ensure you do not lose any data, so assuming your pools are configured using replicas in threefold, after losing two nodes your PGs should be unavailable. This is by design, and for your own safety. I understand it is not what you're asking for, but my two cents would be to understand why the Ceph nodes hung in the first place and act upon it (fix hardware, maybe upgrade firmware, maybe fix software if applicable). Or in addition extend your Ceph cluster, if there's budget for that. (Always go for dual power supplies and don't even consider non-ECC RAM.) Cheers, Kees On 25/02/2026 05:08, Thamanna Farhath wrote:
Dear Community,
We are running OpenStack 2023.1 with Ceph as the backend storage on a 3-node deployment.
Recently, we faced a scenario where two of our servers became unresponsive (hung state), and we had to reboot them. During this time, VMs running on the affected compute node started reporting I/O errors inside the guest OS, such as:
|[ 33.911093] blk_update_request: I/O error, dev vda, sector 229880 op 0x1:(WRITE) flags 0x800 phys_seg 2 prio class 0 [ 33.914953] Buffer I/O error on dev vda1, logical block 319, lost async page write [ 33.914953] Buffer I/O error on dev vda1, logical block 320, lost async page write [ 33.927594] blk_update_request: I/O error, dev vda, sector 229904 op 0x1:(WRITE) flags 0x800 phys_seg 2 prio class 0|
It appears that when Ceph becomes unavailable (or quorum is lost), the VMs continue attempting writes, which results in I/O errors at the guest OS level.
Our goal: We would like to prevent guest filesystem corruption or I/O errors when Ceph is down. Ideally, we want to:
*
Pause or block writes from active VMs when Ceph storage is unavailable
*
Avoid guest OS filesystem corruption
*
Ensure safer recovery when Ceph services are restored
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