---
product_id: 378534395
title: "SilverStone Technology 2U Rackmount Server Case with 4 X 3.5\" Hot Swap Bays Micro-Atx Support RM21-304"
brand: "silverstone"
price: "£1225.83"
currency: GBP
in_stock: true
reviews_count: 5
category: "Silver Stone"
url: https://www.desertcart.co.uk/products/378534395-silverstone-technology-2u-rackmount-server-case-with-4-x-3
store_origin: GB
region: United Kingdom
---

# 4 x 3.5" hot-swap drive bays Micro-ATX motherboard support Tool-less rail design SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304

**Brand:** silverstone
**Price:** £1225.83
**Availability:** ✅ In Stock

## Summary

> 🚀 Elevate your data game with SilverStone’s sleek, rack-ready powerhouse!

## Quick Answers

- **What is this?** SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 by silverstone
- **How much does it cost?** £1225.83 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/378534395-silverstone-technology-2u-rackmount-server-case-with-4-x-3)

## Best For

- silverstone enthusiasts

## Why This Product

- Trusted silverstone brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Compact Powerhouse Design:** Optimized for Micro-ATX boards, balancing space efficiency with robust server performance.
- • **Flexible PSU Compatibility:** Supports both standard and redundant 2U power supplies, ensuring uptime and power reliability.
- • **Tool-Free Rack Integration:** Install or remove the chassis quickly with ergonomic, tool-less rails—because your time is money.
- • **Effortless Hot-Swap Storage:** Seamlessly swap up to four 3.5" drives without downtime, perfect for dynamic data environments.
- • **Engineered for Cooling & Durability:** Precision fan assembly and sturdy build keep your drives cool and your data safe under pressure.

## Overview

The SilverStone RM21-304 is a 2U rackmount server chassis designed for professional storage solutions. It supports Micro-ATX motherboards and features four hot-swappable 3.5" drive bays compatible with 2.5" drives, tool-less rails for easy rack installation, and flexible mounts for standard or redundant 2U power supplies. Engineered for efficient cooling and durability, it’s ideal for data center engineers and professionals seeking a cost-effective, high-performance storage server case.

## Description

Silverstone's rm21-304 is a high performance storage Server Chassis designed for the professional storage environment. It is equipped with hard drive trays compatible with 2.5" Or 3.5" Drives and has fan Assembly with motherboard Support for up to Micro-ATX form factor. There are also flexible mounts to accommodate most 2U single/ 2U redundant server, PS2 (ATX) power supplies. Rm21-304 also has ergonomic, tool-less rail* designs for easy rack mount integration. With an overall package Designed for maximizing efficiency, flexibility, and durability, The rm21-304 is a great choice for professionals or data center engineers looking to build a storage Server.

Review: Great build quality - Pros: -Parts are meticulously organized: bags are labelled for every type of screw you'll need. -Fans are easily replaceable though it's a tight squeeze for standard width fans (25mm). -Fit my XFX 850w ATX power supply perfectly. -Good temps while drives are in use. -It's hard to tell from the photos, but it supports 2x2.5" internal drives (in addition to the hot swap bays). Cons: -An extra half inch of clearance between the fan mounts and the back plane would remove headaches for replacing the fans. Slim fans don't provide much static pressure. -Cable management can be a pain with long cables - get as short as your situation allows. I bought some extra molex cables to connect the back plane to the power supply less of a hassle. May not be necessary for others. The back plane uses 2x mini-sas SFF-8087 connectors. Don't buy breakout cables without realizing like I did. Impressed so far with performance as Unraid host. To buy an equivalent pre-built NAS solution, it would've easily run me 4-5 times as much as I spent for the entire setup + license.
Review: Great Short Depth Chassis for a NAS - Recommended - I was in the market for a 2U chassis for a new NAS system, but my rack is about 24" / 600mm deep (and I don't have room for a deeper rack). It's asking a lot to pack so much server into a small space including 8 hot swappable 3.5" drive bays, but this case is solid, well built, and delivers. I paired this case with the SilverStone Technology 20" Ball Bearing Sliding Rail Kit RMS04-20 (not included). Installing the rails was straight forward and quick. Personally I'd probably prefer a more traditional rail rather than the tool-less design, but this works well. I highly recommend this case if your requirement is specifically for short depth chassis with hot swappable 3.5" drive bays. If your situation allows for a longer chassis, do it - it'll give you more options. A couple of tips based on my experience for your build in this chassis - these are just things to think about, none of these are complaints but are simply facts of life for working in such a short chassis: Power Supply: Plan your power supply early in the build, the depth of the chassis greatly limits your options. You have an option between a 2U or an ATX power supply. For ATX power supplies, most have a fan that would pull air in through vents on the top of the chassis and exhaust through the back, these are easier to find but the vent should have at least 2U of free space above it to pull in the air. ATX power supplies with a front to back ventilation would be preferable but are harder to find. Modular or semi-modular would be a plus to reduce the number of unused cables that need to be managed. For 2U power supplies, higher wattages from well known brands can be too long for this chassis (220mm-260mm). Be careful to leave room in your chassis to manage the power cabling (i.e. don't get too big of a power supply). I went with an ATX power supply measuring 5.91" x 3.39" x 5.51" with front to back ventilation. Chassis Fans: The fans in this chassis come connected to the hard drive back plane. When I first built the system, the fans spun up to full speed briefly at boot and then either slowed to a minimum or turned off completely which led my SAS controller to generate overheating alerts. The fans are standard PWM fans, which I connected to my motherboard allowing me to control and monitor their speeds. Do note, however, that the cables are short and I needed to buy extensions to reach the motherboard (my extensions are 26cm which work but are just a little more snug than I'd like). The fan noise level is reasonable. There is no high pitch whine from the fans, and the wind rushing sound will vary depending upon the speed the fan is rotating at. As with all rack mount systems, don't expect it to be whisper quiet. Hard Drive Backplane: On the backplane side, you'll need to connect 2x Mini SAS SFF-8087 Cables. One cable is for 4 SATA drives on the top row, and the second cable is for the 4 SATA drives on the bottom row. What you need on the other end will of course depend on your motherboard or disk controller. I'm using 2x Mini SAS HD SFF-8643 to Mini SAS SFF-8087 Cable, 0.5-m(1.6ft) for my setup (though I wish I could get a shorter version of the cable!). You'll also need 4x Molex cables to power the backplane. Cabling: It's a small chassis and things are relatively close together. Your experience will vary based on factors including the layout of your motherboard, but try to find shorter cables - long enough to reach of course, but which limits the excess cable length to be managed. It adds up quickly! Everything else is pretty box standard: ITX or MicroATX motherboard. There's space for 2x 2.5mm internal drives and one Slim ODD (12.7mm). The front has 1x USB2 and 1x USB3 port (each with their own cable to the motherboard). I've included a picture of my completed build in this chassis to give you a sense of dimensions and the space you have to work with.

## Features

- New production batch now available at
- https://www.desertcart.com/dp/B0B7KPWB31

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07LB74S6J |
| Brand | SilverStone |
| Brand Name | SilverStone |
| Colour | RM21-304 |
| Compatible Devices | Server |
| Compatible devices | Server |
| Customer Reviews | 4.0 out of 5 stars 44 Reviews |
| Enclosure Material | Metal |
| Global Trade Identification Number | 00844761014537 |
| Is Assembly Required | Yes |
| Manufacturer | SilverStone Technology |
| Manufacturer Part Number | SST-RM21-304 |
| Material | Metal |
| Model Number | SST-RM21-304 |
| Mounting Type | Rack Mount |
| Mounting type | Rack Mount |
| Size | 2U (88.9 mm height) |
| UPC | 844761014537 |

## Product Details

- **Brand:** SilverStone
- **Colour:** RM21-304
- **Compatible devices:** Server
- **Material:** Metal
- **Size:** 2U (88.9 mm height)

## Images

![SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 - Image 1](https://m.media-amazon.com/images/I/61Eh4ET5a3L.jpg)
![SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 - Image 2](https://m.media-amazon.com/images/I/61I9bzxVLQL.jpg)
![SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 - Image 3](https://m.media-amazon.com/images/I/61UxT9MMtVL.jpg)
![SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 - Image 4](https://m.media-amazon.com/images/I/61KHoEdKGZL.jpg)
![SilverStone Technology 2U Rackmount Server Case with 4 X 3.5" Hot Swap Bays Micro-Atx Support RM21-304 - Image 5](https://m.media-amazon.com/images/I/71HExtp17JL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Great build quality
*by R***H on 25 March 2021*

Pros: -Parts are meticulously organized: bags are labelled for every type of screw you'll need. -Fans are easily replaceable though it's a tight squeeze for standard width fans (25mm). -Fit my XFX 850w ATX power supply perfectly. -Good temps while drives are in use. -It's hard to tell from the photos, but it supports 2x2.5" internal drives (in addition to the hot swap bays). Cons: -An extra half inch of clearance between the fan mounts and the back plane would remove headaches for replacing the fans. Slim fans don't provide much static pressure. -Cable management can be a pain with long cables - get as short as your situation allows. I bought some extra molex cables to connect the back plane to the power supply less of a hassle. May not be necessary for others. The back plane uses 2x mini-sas SFF-8087 connectors. Don't buy breakout cables without realizing like I did. Impressed so far with performance as Unraid host. To buy an equivalent pre-built NAS solution, it would've easily run me 4-5 times as much as I spent for the entire setup + license.

### ⭐⭐⭐⭐⭐ Great Short Depth Chassis for a NAS - Recommended
*by J***E on 20 August 2021*

I was in the market for a 2U chassis for a new NAS system, but my rack is about 24" / 600mm deep (and I don't have room for a deeper rack). It's asking a lot to pack so much server into a small space including 8 hot swappable 3.5" drive bays, but this case is solid, well built, and delivers. I paired this case with the SilverStone Technology 20" Ball Bearing Sliding Rail Kit RMS04-20 (not included). Installing the rails was straight forward and quick. Personally I'd probably prefer a more traditional rail rather than the tool-less design, but this works well. I highly recommend this case if your requirement is specifically for short depth chassis with hot swappable 3.5" drive bays. If your situation allows for a longer chassis, do it - it'll give you more options. A couple of tips based on my experience for your build in this chassis - these are just things to think about, none of these are complaints but are simply facts of life for working in such a short chassis: Power Supply: Plan your power supply early in the build, the depth of the chassis greatly limits your options. You have an option between a 2U or an ATX power supply. For ATX power supplies, most have a fan that would pull air in through vents on the top of the chassis and exhaust through the back, these are easier to find but the vent should have at least 2U of free space above it to pull in the air. ATX power supplies with a front to back ventilation would be preferable but are harder to find. Modular or semi-modular would be a plus to reduce the number of unused cables that need to be managed. For 2U power supplies, higher wattages from well known brands can be too long for this chassis (220mm-260mm). Be careful to leave room in your chassis to manage the power cabling (i.e. don't get too big of a power supply). I went with an ATX power supply measuring 5.91" x 3.39" x 5.51" with front to back ventilation. Chassis Fans: The fans in this chassis come connected to the hard drive back plane. When I first built the system, the fans spun up to full speed briefly at boot and then either slowed to a minimum or turned off completely which led my SAS controller to generate overheating alerts. The fans are standard PWM fans, which I connected to my motherboard allowing me to control and monitor their speeds. Do note, however, that the cables are short and I needed to buy extensions to reach the motherboard (my extensions are 26cm which work but are just a little more snug than I'd like). The fan noise level is reasonable. There is no high pitch whine from the fans, and the wind rushing sound will vary depending upon the speed the fan is rotating at. As with all rack mount systems, don't expect it to be whisper quiet. Hard Drive Backplane: On the backplane side, you'll need to connect 2x Mini SAS SFF-8087 Cables. One cable is for 4 SATA drives on the top row, and the second cable is for the 4 SATA drives on the bottom row. What you need on the other end will of course depend on your motherboard or disk controller. I'm using 2x Mini SAS HD SFF-8643 to Mini SAS SFF-8087 Cable, 0.5-m(1.6ft) for my setup (though I wish I could get a shorter version of the cable!). You'll also need 4x Molex cables to power the backplane. Cabling: It's a small chassis and things are relatively close together. Your experience will vary based on factors including the layout of your motherboard, but try to find shorter cables - long enough to reach of course, but which limits the excess cable length to be managed. It adds up quickly! Everything else is pretty box standard: ITX or MicroATX motherboard. There's space for 2x 2.5mm internal drives and one Slim ODD (12.7mm). The front has 1x USB2 and 1x USB3 port (each with their own cable to the motherboard). I've included a picture of my completed build in this chassis to give you a sense of dimensions and the space you have to work with.

### ⭐⭐⭐⭐⭐ Great 2U case option
*by A***N on 9 January 2021*

Great case to work with. Hot swap bays are excellent, although one was slightly mis aligned but easy fix with a flathead! Top is easy to remove for easy repairs. Option to have regular or hot swap PSU's is excellent!

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*Product available on Desertcart United Kingdom*
*Store origin: GB*
*Last updated: 2026-06-29*