How much storage fits in the Synology DiskStation DS923+?
By Devin Chua · Data checked by Owen Nakamura · Updated The Synology DiskStation DS923+ takes 4 drives, up to 96 TB raw, but usable is the number that matters: 4 × 8 TB in SHR gives 21.83 TiB, and it survives 1 drive failing. The gap from raw capacity is parity, and SHR lets you grow with mixed drive sizes.
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CMR NAS drives for the DS923+, by price per TB
Only families with confirmed CMR recording and a 24/7 rating, in stock on Amazon.ca and sized for the DS923+. SMR drives are deliberately kept out.
What sets the DS923+ apart
The predecessor many bought for the drive policy, and still the only four-bay DiskStation with a genuine 10-gigabit upgrade slot. The Ryzen R1600 has only two cores: strong as a file store with ECC RAM, weak for many containers.
Who the DS923+ is for
The DS923+ runs the AMD Ryzen R1600 (2 cores, 4 threads), and Plex users need one fact first: these embedded Ryzens carry no integrated GPU, so the DS923+ cannot hardware-transcode video. It is built for a different job — Synology's app suite, Docker and a light VM or two, backed by 4 to 32 GB of ECC memory. Choose the DS923+ as a dependable ECC all-rounder; for hardware transcoding in this price band, an Intel-based UGREEN or QNAP is the better tool.
How the DS923+'s network shapes the drive choice
The DS923+ ships with 2 × 1GbE, expandable to 10GbE with the E10G22-T1-Mini add-in card, and that rewrites the maths. Ten gigabit is about 1,100 MB/s; a single drive gives 150 to 280 MB/s and a 4-drive array three to four times that, so you close much of the gap without ever quite saturating the link. On the DS923+, for the first time, a 7200 rpm Pro drive earns its price — and the NVMe cache earns its slot by keeping hot data off the spinning disks.
A worked configuration for the DS923+
Seagate IronWolf Pro or WD Red Plus in every bay is the recommendation for the DS923+. At 4 × 8 TB in SHR, the DS923+ lands 21.83 TiB usable, gives up 8 TB to parity, and survives 1 drive failing. Step the same 4 bays of the DS923+ up to 16 TB drives and it holds roughly twice that, at the CA$/TB the live table above shows.
SHR or RAID 6 in the DS923+?
With 4 bays the DS923+ gives a real choice. In SHR it keeps 21.83 TiB of the 4 × 8 TB and survives one failure; RAID 6 spends one more drive for two. The trade tips with large drives: after a failure the DS923+ must read every surviving drive in full to rebuild, which on 20 TB drives runs the better part of a day under peak load. So from 16 TB per drive up, RAID 6 is the calmer choice in the DS923+, and SHR-2 gives the same protection while still using mixed drive sizes.
One rule holds on every NAS, the DS923+ included: use CMR drives, not SMR. SMR drives rewrite overlapping tracks and collapse during a RAID rebuild, dragging a repair from hours into days.
The Synology drive policy on the DS923+
unrestrictedOpen. The 2025 drive restriction explicitly does not apply retroactively: Synology confirms it applies “only to new models from 2025.” In the DS923+ every NAS drive runs without restriction.
The DS923+ at a glance
| Bays | 4 × 3.5-inch SATA and 2.5-inch SATA SSD |
|---|---|
| Maximum raw capacity | 96 TB 4 × 24 TB: the largest drive on Synology's compatibility list for this model. With a DX517 expansion the figure rises accordingly. |
| Processor | AMD Ryzen R1600 (2 cores, 4 threads) |
| Memory | 4 GB, DDR4 ECC SO-DIMM (2 slots) 32 GB official (2 × 16 GB ECC). In practice 64 GB (2 × 32 GB ECC SO-DIMM) also runs; Synology does not endorse it. |
| M.2 NVMe | 2 slots 2 × M.2 NVMe. NVMe cache is unrestricted; an NVMe storage pool requires a Synology-approved drive (that has always been the case here). |
| Network | 2 × 1GbE, expandable to 10GbE with the E10G22-T1-Mini add-in card |
| Operating system | DSM 7.x |
| RAID types | SHR, SHR-2, Basic, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 SHR also makes use of mixed drive sizes. |
Keep calculating
To see how much capacity is left after parity, the DS923+ capacity calculator is preset to its 4 bays and RAID types. For the DS923+, the wider basics of choosing a drive are in the buying guides, where we also explain why CMR rather than SMR is mandatory in any RAID array.
Frequently asked questions
What is the maximum storage in the DS923+?
4 drives, up to 96 TB raw per the manufacturer. 4 × 24 TB: the largest drive on Synology's compatibility list for this model. With a DX517 expansion the figure rises accordingly.
How much of the DS923+ is actually usable?
In the DS923+, 4 × 8 TB in SHR yields about 21.83 TiB — that is 24 TB in drive-maker terms, with 8 TB to parity. It shows less than the label because it counts in powers of two.
Can I fit larger drives in the DS923+ later?
Yes, and with SHR it is easy: swap the DS923+'s drives for larger ones one at a time, and the gain arrives once the second-largest drive is also larger.
Can I put third-party drives in the DS923+?
Yes, without restriction. The 2025 Synology drive lock covers only the 2025 models, so the DS923+ takes any NAS drive and has always done so.
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)