LINBIT DRBD vs XtreemFS

LINBIT DRBD is open-source distributed replicated block storage software for Linux, used in high-availability setups. Its kernel driver mirrors writes to one or more peer nodes; in synchronous mode, a write completes only after local and peer storage completion events. Reads can be served locally without network traffic, and the data path avoids user-space components. DRBD combines the kernel driver with user-space management applications and shell scripts, and its command-line interface can manage large clusters without relying on cloud, virtualization, or container platforms. It supports TCP/IP and RDMA/Verbs transports, including InfiniBand, iWARP, and RoCE. The DRBD 9 guide documents TLS encryption for TCP transport. LINBIT also offers WinDRBD for Windows and says its subscriptions integrate with Kubernetes and other major platforms. The open-source community version is free; LINBIT Starter is $1,000 a year, starting from $1,000 for two nodes. The company is headquartered in Vienna, Austria.

XtreemFS is a free, fault-tolerant distributed file system for general-purpose storage, available for Linux, macOS, Windows and self-hosted deployments. Files are replicated across storage servers, with automatic failover to a backup replica if the primary fails. Full or partial read-only replicas support immutable files and can be used to create caches across datacenters. The project says an installation can grow to thousands of storage and metadata servers by adding or removing storage servers. POSIX compatibility makes it usable as an NFS replacement. SSL and X.509 certificate support are built in, and the site says XtreemFS can run over the internet without a VPN. A Hadoop client supports use as an HDFS replacement. Listed uses include filer replacement, HPC and Hadoop clusters, VM block storage and cross-branch sharing. Linux distribution packages and precompiled Windows and Mac OS X clients are available. The FAQ says a single volume may hold up to tens of millions of files, with no known limits stated for volumes and services. The project is open source under a BSD license and is developed by Zuse Institute Berlin.