ASUSTOR LOCKERSTOR 4RS (AS6504RS) review

The LOCKERSTOR 4RS is a small-business rack NAS for a buyer who already has a suitable cabinet and wants four internal SATA positions in a 1U chassis. Its name is easy to confuse with the LOCKERSTOR 4RD, but the last letter changes an important equipment decision: ASUSTOR lists one 250-watt power supply for the AS6504RS and two for the distinct AS6504RD. This assessment is based on manufacturer documentation, not hands-on use or a performance test.

Four native SATA bays, not an expandable desktop tower

ASUSTOR's product-ID-74 hardware table lists four hot-swappable positions for 3.5-inch SATA hard drives, 2.5-inch SATA hard drives, or 2.5-inch SATA SSDs. A four-bay chassis suits a small shared-storage or backup repository where the owner wants more choices than a two-bay enclosure, but it is not a capacity guarantee: installed drive models, RAID layout, formatting, and the current compatibility list matter. The spec page's 72-TB maximum is raw arithmetic based on four 18-TB drives, not usable space or proof that a particular disk-and-firmware combination is supported.

The four front trays are the model's native bays. ASUSTOR separately lists a maximum of 20 bays with an expansion unit; that is not a count of trays inside the AS6504RS, and the additional hardware is not part of the base unit in the package listing. The specification does not list onboard M.2 drive slots. Confirm the exact drive model and firmware in ASUSTOR's current compatibility resource before building a volume; this review did not verify a named drive tuple.

A mirror can use two bays, but it is not a backup

The model's software list includes RAID 1, and ASUSTOR's RAID calculator describes a two-drive minimum. One possible owner-created plan uses two compatible SATA drives in a mirror, leaving two of the four native bays open. That explains why a buyer who requires a two-drive redundant arrangement can include this model in a four-bay shortlist. It does not mean the enclosure ships with disks, an initialized array, or verified compatibility for every retail hard drive. The package page lists the NAS and accessories, not data drives.

RAID 1 can keep a volume available after one member drive fails, but it is not protection against deletion, malicious encryption, fire, theft, or a failed NAS. Keep a second copy on an independent target and plan a restore test. Also separate disk redundancy from power redundancy: the AS6504RS's single listed PSU is not the dual-supply configuration of the AS6504RD. Choosing a mirror does not make the power path redundant.

Two 2.5GbE ports, with an optional PCIe route

ASUSTOR lists two individual 2.5-Gigabit Ethernet ports and two individual 1-Gigabit ports. The fastest built-in single port is therefore 2.5GbE. The two 2.5GbE ports can be configured for aggregation or failover, but that does not turn them into one 5Gbps connector or promise a particular file-transfer rate for one client. A switch or router, client NIC, cabling, disk layout, protocol, and workload all affect the actual path.

A PCIe 3.0 x8-size slot with an x4 electrical link is listed for optional network-card expansion; ASUSTOR's accessory listing identifies the AS-T10G2 as compatible with the AS6504RS. The card is an additional component, not part of the stock built-in-port facts or the listed package. A buyer requiring a factory-built-in 10GbE port should not treat this model as a match just because a separate card can be installed.

Rack fit and package details deserve a model-code check

The manufacturer gives dimensions of 44 × 439 × 515 mm (height × width × depth) and a weight of 7.85 kg: this is a 1U rack unit, not a compact desktop NAS. Measure usable depth and allow for front-to-back clearance, cables, ventilation, and access to the rear. The English quick-install guide has a rail-kit installation section, and ASUSTOR lists a separate AS-Rail accessory for rackmount systems. The model's base package list does not include rails. A Japanese distributor page also shows a regional AS6504RS/RAIL offer, which is not evidence that a U.S. seller's listing has the same bundle. Check the exact seller suffix, rack-rail contents, drive bundle, return terms, and warranty before ordering.

The package listing differentiates one AC cord for the AS6504RS from two for the AS6504RD; it also lists two RJ-45 cables and screws, but no data drives. This matters if a buyer is comparing an RS and RD card by title alone. The model support table currently lists the shared AS6504RS/RD family as Generally Available, with software and technical support marked Supported and a three-year entry. A regional distributor labels its Japanese listing end-of-life, so neither result establishes a live U.S. offer or channel warranty.

Who should shortlist it?

Consider the AS6504RS when four native SATA bays, an existing rack, an individual built-in 2.5GbE path, and a possible owner-created RAID 1 plan fit the job. It is less compelling when a buyer has no rack, needs dual power supplies in the base model, wants built-in 10GbE, or expects drives and rails in the box. The C3538 quad-core processor, 8 GB DDR4 preinstalled memory, four SO-DIMM slots, and listed 128-GB ceiling describe hardware options, not a promise about application speed; check compatible modules and the installation guide before upgrading.

For this review, exact seller configuration, current U.S. stock, exact drive/firmware fit, usable capacity, and real network throughput remain unverified. Compare the actual full model and package contents rather than assuming a seller's “4RS” title identifies a rail bundle or installed drives.