Proxmox Server Solutions released Proxmox Backup Server 4.1 on 2025-11-26, bringing user-based traffic limiting and configurable verification parallelism to the open-source enterprise backup platform. Built on Debian 13.2 "Trixie" with Linux kernel 6.17 and ZFS 2.3, the update extends existing network-based traffic control with per-user bandwidth prioritization, allowing administrators to assign higher backup speeds to business-critical services or separate production and test environments at the user level.
The release introduces configurable threading for verification jobs, addressing the CPU and I/O demands of validating backup checksums. Administrators can now adjust the number of threads used for disk reads and checksum verification, potentially reducing verify runtimes significantly depending on hardware. This helps balance verification tasks against other resource-intensive operations on the same system.
Proxmox Backup Server 4.1 also adds bandwidth rate limiting for S3-compatible object storage endpoints, building on native S3 support introduced in version 4.0. The feature prevents network congestion between backup server instances and object storage infrastructure in shared or bandwidth-constrained environments.
The software is available immediately as an ISO download or via APT upgrades from previous versions, published under the GNU AGPLv3 license. Enterprise support subscriptions start at €540 ($587) per server per year with unlimited backup storage and clients.