Cristie CloneManager vs XtreemFS

Cristie CloneManager Replication provides continuous system replication across physical, virtual and cloud environments. It supports file-based and block-based replication; block-based replication can lower recovery point objectives compared with file-based replication. Replication can target virtual disk image files in VHDX, QCOW2 and VMDK formats, as well as AWS, Azure, Oracle Cloud and S3 blob storage. The software monitors source systems and can automatically fail over after an outage, with DNS changes if needed. Multiple systems and their failover and failback can be managed through one interface. Teams can create sandbox test environments, including on physical systems, without interrupting continuous replication. RPO monitoring includes reports and email notices when replication falls outside target RPOs. The supported systems matrix includes Windows and Linux and virtualization platforms such as VMware vSphere, Hyper-V, AWS EC2, Microsoft Azure and Oracle Cloud Infrastructure. Replication costs $500 a year per protected system, with 12 months of support and maintenance. A free trial is offered, but no fixed duration is stated.

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.