TerraMaster T6-423: A compact and quiet NAS with plenty of storage

Some TOS 5 apps aren't ready yet, but this affordable desktop NAS offers plenty of storage features and good performance

TerraMaster T6 NAS drive

IT Pro Verdict


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    Strong security options

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    Solid performance

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    Value for money


    Small businesses that want plenty of network storage on their desktop will find TerraMaster's T6-423 NAS appliance could be just the ticket. This small footprint box puts six hot-swap LFF/SFF SATA drive bays on the table and pairs them with dual 2.5GbE multi-Gigabit ports.

    Inside you have a 2GHz quad-core Intel Celeron N5105 CPU partnered with 4GB of DDR4 memory, upgradable to 32GB using the two SODIMM slots. The appliance also has two M.2 NVMe SSD slots that can be used as a performance-enhancing cache or as a standard storage pool.

    The appliance is well built, with a solid steel chassis and metal drive carriers. Two rear 9cm diameter fans handle all cooling, and we found them to be extremely quiet, making this a great choice for small offices.

    For testing, we used four 14TB WD Red Pro hard disks and slotted in two 480GB NVMe SSDs. These were easy to fit, by removing the side cover to access the motherboard. For memory upgrades, the second SODIMM slot is underneath the motherboard, which is connected to the backplane with a single-edge connector and only takes a minute to remove.

    Before installation, you'll have to decide which version of TerraMaster's operating system (TOS) you want to use. The freshly launched TOS 5 uses new root file systems, storage paths and startup methods, so upgrading from earlier versions requires a full backup and

    system reset. We opted to download the TOS 5 package and used the quick start wizard's custom mode to manually install it.

    terramaster's operating system user interface

    There is an abundance of new features; along with a more responsive web interface, TOS 5 supports TRAID arrays, which are similar to the Synology Hybrid Array (SHR), meaning that they can use drives of different sizes without the capacity overheads incurred with

    traditional arrays.

    Security is centre stage, with the HyperLock-WORM feature allowing volumes to be assigned custom retention periods of up to 70 years to prevent stored data being modified or deleted. Once set, the period can't be decreased, and TerraMaster applies this to standard Btrfs volumes - Qnap and Qsan can only do WORM on their ZFS-based file systems.

    You create your own administration account as a default admin user isn't provided during installation. And if you're worried about the NAS being attacked, the System Isolation Mode blocks all internet, SSH and Telnet access, and you can stop unsigned apps running with one click.

    Plenty of apps are available for the T6-423 -- a total of 52, in fact - and include tools for cloud file syncing, data protection, surveillance and multimedia, with the new Snapshot app now supporting both NAS shares and iSCSI LUNs.

    The centralised Backup app is still in beta testing and it failed with unknown errors when we tried to secure our Hyper-V host, while protection jobs for our VMware system simply refused to run. TerraMaster advised us that it is currently working on fixes.

    Performance is good, with a share mapped over a 2.5GbE link to a Dell PowerEdge T640 Windows server delivering Iometer sequential read and write rates of 2.3Gbits/sec and 2.1Gbits/sec. Real-world speeds are up there too, with copies of a 25GB test file between the appliance and server averaging read and write rates of 2.3Gbits/sec and 2Gbits/sec, while securing 10,500 small files to the appliance returned 1.3Gbits/sec.

    The T6-423 delivers in the IP SAN stakes, with a 1TB iSCSI target returning sequential read and write rates of 2.3Gbits/sec and 2.2Gbits/ sec, ramping up to 4.6Gbits/sec and 4Gbits/sec for a dual 2.5GbE MPIO iSCSI link. We assigned a mirrored SSD cache to the volume containing the MPIO target and watched it deliver improvements of 1% and 656% for random read and write IOPS.

    The T6-423 is a compact and quiet NAS that puts plenty of storage on your desktop at a good price. A few TOS 5 apps are still in development, but it offers great security features and delivers a nippy 2.5GbE performance.

    TerraMaster T6 Specifications

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    ChassisDesktop chassis
    Processor2GHz Intel Celeron N5105
    Storage4GB DDR4 (Max 32GB)
    Ports2 x M.2 2280 NVMe slots, 2 x USB 3, HDMI
    Dimensions130 x 218 x 226mm (WDH)
    Dave Mitchell

    Dave is an IT consultant and freelance journalist specialising in hands-on reviews of computer networking products covering all market sectors from small businesses to enterprises. Founder of Binary Testing Ltd – the UK’s premier independent network testing laboratory - Dave has over 45 years of experience in the IT industry.

    Dave has produced many thousands of in-depth business networking product reviews from his lab which have been reproduced globally. Writing for ITPro and its sister title, PC Pro, he covers all areas of business IT infrastructure, including servers, storage, network security, data protection, cloud, infrastructure and services.