NexentaStor is a proprietary derivative operating system built by the developers of the open-source Nexenta OpenSolaris-distribution that has been optimized for use virtualized server environments NAS and iSCSI and Fibre Channel applications built around the ZFS file system.
It features iSCSI support, unlimited incremental backups or 'snapshots', snapshot mirroring (replication), block level mirroring (CDP), integrated search within ZFS snapshots and a custom API.
Through its focus on ZFS, it carries with it potential benefits for virtualized server farms in terms of performance and thin provisioning. The operating system is currently distributed as ISO and VMWare disk images with pricing determined on a per-terabyte and per-server licensing basis.A "community edition" is available free of charge for users with less than 12 terabyte of used disk space.
Updates: (via Distrowatch)
Garrett D'Amore has announced the release of NexentaStor 3.1, an enterprise-class storage solution built upon the foundation of the OpenSolaris-based Nexenta Core Platform: "After a long and arduous release cycle, I am pleased to report that NexentaStor 3.1 is available now. This release includes a number of key features, including some significant improvements for performance and manageability. Folks using SCSI target mode will probably see the biggest performance boost relative to earlier versions of NexentaStor, especially those folks using NexentaStor to serve up storage to VMware guests -- thanks to the VAAI offload support that is part of this release. And yes, this release includes the fix the long-standing problem with iSCSI timeouts. For ZFS fans, this release also includes the updates for ZFS version 28."
Read the complete release announcement for further information.