The FX2421 24-Bay Expansion Unit from Synology is designed to provide storage expansion for their FlashStation units. It can also be used as a dedicated and rapidly accessible local backup destination.

The 24 drive bays of the FX2421 natively support 2.5" SAS hard drives and solid-state drives, as well as SATA solid-state drives, including Synology's SAT5200 SATA SSD. The drives are hot-swappable and connectivity for the FX2421 is established using one SAS input and one SAS output. It operates using dual redundant power supplies and includes an accessory pack, two AC power cords, and an expansion cable.

For Synology FlashStation Units    24 x 2.5" SAS/SATA Drive Bays    1 x SAS Input | 1 x SAS Output    Hot-Swappable Drives    Supports Synology's SAT5200 SATA SSD    Dual Redundant Power Supplies

It is easy to expand your Synology FlashStation with the Expansion Unit FX2421 for 24 additional 2.5" drive bays whenever needed. Without additional software configuration, the FX2421 is immediately ready for use when connected to any Synology FlashStation. FX2421 expansion units can also be used as dedicated and rapidly accessible local backup destinations.

Synology's SAT5200 SATA SSD, developed in tandem with the FX2421, provides proven interoperability and high reliability through rigorous validation and compatibility testing with Synology Expansion Units. Synology's SAT5200 solid-state drive delivers up to 67,000 4K random write IOPS and enterprise-grade endurance at 1.3 DWPD. Combine SAT5200 drives with the Synology FlashStation and FX2421 for a highly reliable integrated storage setup and receive long-term Synology updates and support.

The high-speed expansion cable provided with the FX2421 enables high bandwidth connectivity for maximum data throughput between your Synology FlashStation and Expansion Unit. Drives in the FX2421 operate with minimum data latency, as if installed directly on your Synology FlashStation, allowing you to take advantage of high SSD I/O performance.

The FX2421 is a highly reliable and thoroughly tested expansion unit that comes with hot-swappable drive trays and modularized components. Redundant power supplies and system fans can be replaced with ease to ensure maximum service uptime. The optional RKS1317 sliding rail kit provides fast rack fixing lock support for quick and secure rack cabinet installation.

Synology's FX2421 is designed to keep your data durably safe and is backed by Synology's 5-year limited warranty, which includes hardware replacement and technical support for maximum return on investment.

Related Questions and Answers

Q: 1. Can I migrate my current HDS5C4040ALE630 (HGST 4TB Drives) from my old DS1513+ to this DS1522+ device?

A: The HDS5C4040ALE630 HDDs are not listed as compatible with the Synology DiskStation DS1522+ 5-Bay NAS Enclosure. I order to migrate your data will need to populate the DS1522+ with drives that are compatible, like the WD 4TB WD40EFPX Red Plus SATA III 3.5" Internal NAS HDD (B&H # WEDBC9V004H1, MFR #WDBC9V0040HH1-WRSN) then use the Synology Migration Assistant to migrate your DS1513+ to the DS1522+.

Q: 2. when i buy this do i just add my hdd's to have it working on my network as a nas or do i have to buy extra stuff?

A: The Synology DiskStation DS1821+ 8-Bay NAS Enclosure comes with Ethernet cables for you to set it up, and you just need the proper hard drive to start (it is recommended to use NAS-rated drives). You can also upgrade it with two M.2 (2280) drives and/or utilize the enclosure's PCIe 3.0 (x8) expansion slot, but it's not mandatory.

Q: 3. Does latest Synology firmware/software support larger than 18tb drives yet?

A: The Synology DiskStation DS1522+ 5-Bay NAS Enclosure does show compatibility with a 20TB Drive, model HAT5310-20T.

Q: 4. Can oui mix HDD and SSD in the same machine, likeby using 3 SSD and 2 HDD? Can we use different different storage capacit for HDD, like 2 16 T and one 12T or they all have to be the same? Thank you

A: It is possible to mix storage types in a Synology NAS, but when doing so it is recommended to use the different types of drive in separate storage pools. A RAID storage volume containing both an HDD and an SSD will only be able to run at the slower speed of the HDD, so the enhanced speed of the SSD would be wasted.

Q: 5. Would this system be good for editing video with 4 - 4k edit stations attached ?

A: Yes, this unit is purpose built for high speed workgroup access, but requires the correct infrastructure to do so.

Q: 6. Does this nas support lossless compression for video/photo?

A: Yes, you can store lossless compressed files on the Synology DiskStation DS223j 2-Bay NAS Enclosure.

Q: 7. Hi, is it necessary to have both drives of the same capacity or is it possible to have one 16TB drive and a 12TB drive?

A: It is possible to use hard drives with different capacities in each bay of the Synology DiskStation DS224+ 2-Bay NAS Enclosure, B&H # SYDS224PLUS. Keep in mind that if you intend to use traditional RAID 0 or 1, you will lose the extra capacity of the larger drive. For example, if you have a 16TB drive and a 12TB drive in a RAID 0 configuration, the total usable capacity will be 12TB.

Q: 8. The specs say this NAS supports macOS 10.12 and later. Does this mean you won't be able to back up a Mac running an earlier OS, like 10.11, to this NAS?

A: That is correct.

Q: 9. I am deciding between this unit and OWC Thunderbay 8 bay Raid. I need a fast/reliable HD array for video editing, not NAS?

A: For an 8-bay RAID that's directly accessed rather than network-accessed, I recommend the OWC ThunderBay 8 8-Bay Thunderbolt 3 Raid Array with SoftRAID XT (B&H # OWTB38SRKIT0, https://bhpho.to/3nyXhCJ) over the Synology DiskStation DS1821+ 8-Bay NAS Enclosure (B&H # SYDS1821P, https://bhpho.to/3nGCSLT). The OWC model has faster Thunderbolt 3 ports to plug in and access directly from your computer, while the Synology is designed as a network-based backup solution.

Q: 10. What is the best HDD can be used with this product?

A: You can choose from these: https://www.bhphotovideo.com/c/search?q=ironwolf%20nas&sort=PRICE_LOW_TO_HIGH&filters=fct_capacity_844%3A18tb%7C16tb%7C14tb%7C12tb%7C10tb%7C8tb%7C6tb%7C4tb%7C3tb%7C2tb%2Cfct_category%3Ainternal_drives_6525%2Cfct_form-factor_2238%3A3.5in