Synology DiskStation DS224+: capacity calculator
By Devin Chua · Data checked by Owen Nakamura · Updated In the Synology DiskStation DS224+ with 2 × 8 TB in SHR you keep 7.28 TiB usable (8 TB in drive-maker terms), surviving 1 drive failing. The calculator below is preset to the 2 bays and the RAID types DSM 7.x actually offers on this model (including SHR, which uses mixed drive sizes), with the cost to fill in Canadian dollars from live Amazon.ca prices.
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Preset for the DS224+: 2 bays, and only the RAID types this model actually supports.
SHR (Synology Hybrid RAID)
That is 8 TB the way drive makers label capacity. Your NAS shows you the smaller number because it counts in powers of two.
Drives: from CA$1,008 for 2 × 8 TB (CA$63.01/TB overall)
What to know about the DS224+
The best-selling two-bay DiskStation and enough for most homes. With two bays, RAID effectively means RAID 1: you pay half the capacity for fault tolerance, and SHR changes nothing with two equal-size drives.
The DS224+ at a glance
| Bays | 2 × 3.5-inch SATA and 2.5-inch SATA SSD |
|---|---|
| Maximum raw capacity | 48 TB 2 × 24 TB: the largest drive on Synology's list for this model. |
| Processor | Intel Celeron J4125 (4 cores) |
| Memory | 2 GB stock, DDR4 SO-DIMM, no ECC (2 GB soldered plus 1 slot) 6 GB official (2 GB fixed plus a 4 GB module). Larger modules run in practice but are not endorsed. |
| M.2 NVMe | none No M.2 slots |
| Network | 2 × 1GbE |
| RAID types | SHR, Basic, JBOD, RAID 0, RAID 1 |
| Third-party drives | unrestricted Open. The 2025 restriction does not apply retroactively; every NAS drive works. |
SHR is the real reason to buy the DS224+
SHR subtracts only the largest drive from the total, instead of sizing to the smallest like RAID 5. On the DS224+ that means you can start with two drives, add a larger one later, and actually use the gain. UGREEN and QNAP have no equivalent, and with mismatched drives that freedom is quickly worth several hundred dollars. With equal-size drives SHR is arithmetically the same as RAID 5, so there it is simply preference.
Two bays means RAID 1 in practice on the DS224+
With two drives there is no sensible alternative to RAID 1 on the DS224+ (or SHR with two drives, which is arithmetically the same). You pay half your capacity for fault tolerance: 2 × 8 TB becomes 8 TB, not 16. RAID 5 needs at least three drives and is not available here. For more capacity per dollar without giving up safety, a four-bay model is the move.
Which drives belong in the DS224+?
CMR NAS drives rated for 24/7 use — Seagate IronWolf, WD Red Plus, Toshiba N300 or their Pro variants. Our drive picks for the DS224+ with live prices show which of those currently offers the best capacity per dollar. If you are working back from a target capacity instead, the drive-count calculator works out how many drives you need.
Frequently asked questions
How much storage is left in the DS224+ with 2 × 8 TB?
About 7.28 TiB usable — 8 TB in drive-maker terms — computed in SHR, the sensible default for this model. It survives 1 drive failing. The gap from the 16 TB raw goes to parity.
Which RAID types does the DS224+ support?
DSM 7.x offers SHR, Basic, JBOD, RAID 0, RAID 1 on the DS224+. SHR is the one that matters: it lets the DS224+ use mixed drive sizes instead of leveling every drive down to the smallest.
Can I put third-party drives in the DS224+?
Open. The 2025 restriction does not apply retroactively; every NAS drive works.
How much memory does the DS224+ take?
It ships with 2 GB (DDR4 SO-DIMM, no ECC (2 GB soldered plus 1 slot)). 6 GB official (2 GB fixed plus a 4 GB module). Larger modules run in practice but are not endorsed. There is one slot.
Why does my NAS show less than the calculator says?
Because the maker and the OS count differently. A drive maker calls one trillion bytes a TB; the NAS counts in powers of two and calls that a TiB — about 9 percent less. That is why this calculator leads with the TiB figure: it is the number you will read off the screen.
Devin Chua works out which drives, RAM and NVMe cache fit which NAS model at nasdrives.ca, and what the RAID choice means for usable capacity, checked against what is in stock on Amazon.ca.
Data checked by Owen Nakamura, Technical editor (data checking)