TrueNAS (formerly FreeNAS) is an operating system that can be installed on virtually any hardware platform to share data over a network. TrueNAS is the simplest way to create a centralized and easily accessible place for your data.
TrueNAS vs SnapRAID opinions
SnapRAID isn't a NAS, it can be installed into FreeNAS if you so wish. It's more a periodic parity + hash calc tool to augment storage. For FreeNAS it's not really necessary as the ZFS file system pretty much does what SnapRAID does - only in real time instead of periodic.
An operating system for personal and small business use that brings enterprise-class features letting you configure your computer systems to maximize performance and capacity using any combination of applications, VMs, storage devices, and hardware.
It uses openSUSE Leap as a base with the Btrfs advanced file system. EasyNAS is managed through a web-based interface and offers such features as on-line growing of file systems, snapshots and copy-on-write.
Rockstor is a free and open source NAS (Network Attached Storage) operating system. It’s a software solution and can be installed on commodity hardware or a hypervisor satisfying minimum system requirements.
Unify & organize your data. Protect & recover from disk failures! Whether you are choosing Transparent RAID™ or RAID over File System, FlexRAID products allow you to transform a common PC with an existing operating system into a protected Network Attached Storage (NAS)...This app doesn't have any features at the moment.Discontinued
flexraid is no longer being supported and the website has gone dark.
Enterprise Storage OS® is a quasi Linux distribution based on the excellent SCST project; its purpose is to provide SCSI targets via a compatible SAN (Fibre Channel, InfiniBand, iSCSI, FCoE). In a nutshell, ESOS® can easily turn a server with the appropriate hardware...This app doesn't have any features at the moment.