The Synology DS718+ is a high-end 2-bay NAS with good performance, silent operation, and low power consumption. Its strong advantage is that its storage capacity can easily be expanded with five additional drives (seven in total) since it is compatible with the optional DX513 expansion unit.

The DS718+ is a high-end NAS featuring two bays, which looks like very little when it comes to its capacity; however, this NAS is compatible with Synology's DX517 expansion unit, so you can turn it into a NAS with seven bays if more storage is required. The only problem is that the DX517 isn't cheap since it actually costs more than the DS718+, but what matters is that this NAS server's storage space can be expanded upon when the need to do so arises.

Thanks to its quad-core CPU, the DS718+ supports real-time 4K video transcoding, which makes it ideal for users wanting a NAS for high quality multimedia content streaming. Priced at $400 as I write this review, it surely isn't an affordable 2-bay NAS servers, but its feature set is rich and among others includes support for both Btrfs and ext4. The Btrfs filesystem offers better data protection than ext4, so Synology recommends formatting the server's drives to Btrfs instead of ext4. Btrfs also supports a maximum file size of 16 EiB instead of the 1 EiB in ext4 and includes other interesting features, like snapshots, pooling, and checksums.