How much storage fits in the Synology DiskStation DS1525+?

What sets the DS1525+ apart

Five bays is the interesting number: only from five drives does SHR-2 with double fault tolerance become economical without giving up more than a third of the capacity. Unlike the DS925+, the DS1525+ takes a 10-gigabit card.

Who the DS1525+ is for

The DS1525+ runs the AMD Ryzen V1500B (4 cores, 8 threads), and Plex users need one fact first: these embedded Ryzens carry no integrated GPU, so the DS1525+ cannot hardware-transcode video. It is built for a different job — Synology's app suite, Docker and genuine virtual machines, backed by 8 to 32 GB of ECC memory. Choose the DS1525+ 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 DS1525+'s network shapes the drive choice

The DS1525+ ships with 2 × 2.5GbE, expandable to 10GbE with the E10G22-T1-Mini, and that rewrites the maths. Ten gigabit is about 1,100 MB/s; a single drive gives 150 to 280 MB/s and a 5-drive array three to four times that, so you close much of the gap without ever quite saturating the link. On the DS1525+, 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 DS1525+

Seagate IronWolf Pro or WD Red Plus in every bay is the recommendation for the DS1525+. At 5 × 8 TB in SHR, the DS1525+ lands 29.10 TiB usable, gives up 8 TB to parity, and survives 1 drive failing. Step the same 5 bays of the DS1525+ 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 DS1525+?

With 5 bays the DS1525+ gives a real choice. In SHR it keeps 29.10 TiB of the 5 × 8 TB and survives one failure; RAID 6 spends one more drive for two. The trade tips with large drives: after a failure the DS1525+ 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 DS1525+, and SHR-2 gives the same protection while still using mixed drive sizes.

One rule holds on every NAS, the DS1525+ 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 DS1525+

with a caveatPartly open, like the DS925+. Since DSM 7.3 (8 October 2025) third-party hard drives and SATA SSDs are unrestricted again; only M.2 NVMe stays tied to the Synology list.

The DS1525+ at a glance

Keep calculating

To see how much capacity is left after parity, the DS1525+ capacity calculator is preset to its 5 bays and RAID types. For the DS1525+, 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