Synology HAS5320-24T is the 24TB SAS member of Synology's enterprise HDD line. It should be evaluated as a SAS storage-system component, not as a normal DiskStation drive upgrade.
The physical 3.5-inch size is not enough. SAS requires a SAS-capable controller, backplane and Synology system class. Buyers filling ordinary SATA-only DiskStation bays should be looking at HAT5320, not HAS5320.
Choose HAS5320-24T for Synology SAS-capable rackmount, high-availability or enterprise systems where SAS pathing, qualification and DSM-managed firmware support are required. Do not buy it for a SATA-only DiskStation, QNAP, desktop NAS or workstation bay. If the system is SATA, the comparable first-party Synology drive is HAT5320-24T.
Manufacturer-published values for the exact product family. Retail listings can collapse these details, so match the part number before ordering.
| Spec | Value |
|---|---|
| Model number | HAS5320-24T |
| Capacity | 24TB decimal marketed capacity |
| Recording technology | CMR in current HAS5320-24T product-spec/channel data; verify the exact procurement document if recording method is a purchase-order requirement |
| Platform | Synology-qualified 3.5-inch enterprise SAS HDD for SAS-capable rackmount and high-availability systems |
| Interface | SAS 12Gb/s |
| Sector format | 3.5-inch enterprise SAS HDD; exact sector behavior should be checked against the selected Synology system |
| Spindle speed | 7200 RPM |
| Cache / buffer | 1GiB / 1024MB in current product-spec/channel data; not exposed in the crawlable Synology product table |
| Maximum sustained transfer rate | 309MB/s maximum sustained data transfer speed, typical |
| Workload rating | 550TB/year |
| Reliability rating | Up to 2.5M hours |
| Warranty | 5-year limited warranty |
| Power | 4.83W active idle; 8.57W random read/write 4KB Q1 typical |
| Acoustics | Synology's public product page does not expose an acoustic row; rackmount acoustic planning should use the full system spec. |
| Operating temperature | 5C to 60C operating; -40C to 70C non-operating |
| Compatibility note | For SAS-capable Synology HD, SA, UC and related enterprise systems; not a SATA DiskStation upgrade. |
No exact in-stock live row is currently matched for HAS5320-24T. Relevant live alternatives are shown so the page does not collapse into an empty catalogue.
Live prices · updated every 4-5 hours · last checked 5 hr ago · exact model not currently matched in live stock
| Model | Capacity | Recording | RPM | Workload TB/yr | Warranty | $/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 12TB HAS5300-12T | 12TB | CMR | 7,200 | — | 5 yr | $55.83 | $670 | Buy |
| 16TB HAT5310-16T | 16TB | CMR | 7,200 | — | 5 yr | $63.25 | $1012 | Buy |
Workload rating is recorded per part number from Seagate's datasheet for that exact model, not blanketed across the line — two drives of the same capacity can differ because they are different generations. A dash means the figure is not stated for that listing. Recording technology comes from the manufacturer's published CMR/SMR list; a model absent from that list is shown as UNVERIFIED rather than guessed. Rows priced above 3× this line's in-stock median are flagged and excluded from the winner callout and from every median we compute.
This table is computed from live DatacenterDisk rows when an exact in-stock match exists. It is intentionally blank for unavailable models rather than filled with stale prices.
| Live model | Drive price | $/TB | 100TB raw target | 500TB raw target | 1PB raw target |
|---|---|---|---|---|---|
| No exact in-stock row is available right now. Use the availability table for nearby live alternatives, then re-check the exact model before ordering. | |||||
Raw capacity is not usable capacity. This table shows the slot-level math before filesystem overhead, snapshots, reserved space and vendor-specific parity layouts.
| Drive count | Raw capacity | Single-parity usable | Dual-parity usable |
|---|---|---|---|
| 4 bays | 96TB | 72TB | 48TB |
| 6 bays | 144TB | 120TB | 96TB |
| 8 bays | 192TB | 168TB | 144TB |
| 12 bays | 288TB | 264TB | 240TB |
A SAS drive decision is a system-architecture decision, not just a capacity choice.
| Check | Required answer | Reason |
|---|---|---|
| System class | SAS-capable Synology enterprise/rackmount platform | DiskStation SATA bays cannot use a SAS drive. |
| Backplane | SAS 12Gb/s compatible | The connector path, not the 3.5-inch form factor, decides compatibility. |
| Controller path | SAS HBA/controller and any multipath design qualified | SAS value comes from enterprise pathing, not from faster spinning media. |
| Drive list | HAS5320-24T appears for the exact system or expansion shelf | Synology support depends on exact qualification. |
| Spare strategy | SAS spares stocked separately from HAT SATA spares | HAT and HAS are not interchangeable in a failed-bay event. |
The key difference between HAS5320 and HAT5320 is the host interface. HAS5320 is SAS 12Gb/s. HAT5320 is SATA 6Gb/s. The media capacity and broad enterprise class are similar, but the systems that can use them are not.
SAS matters in rackmount storage because it supports enterprise controller paths and redundancy designs that SATA bays do not provide. That does not mean the platters are magically faster. The public Synology page lists the same 309MB/s typical maximum sustained transfer speed for the 24TB HAS and HAT models.
Synology positions the HAS enterprise SAS line for systems such as HD, SA and UC class platforms, where the storage architecture is built around enterprise racks, controller redundancy and SAS connectivity. It is a business-continuity part as much as a hard drive.
If the buying environment involves dual-controller storage, high-availability planning or SAN-oriented Synology hardware, HAS5320 can be exactly the right first-party option. If the host is a desktop DiskStation, the SAS feature set is irrelevant because the drive will not fit the electrical path.
A 3.5-inch SAS HDD does not work in a SATA-only slot. This is the mistake the page is designed to prevent. The latch, tray and physical bay can look familiar while the controller path is entirely different.
Before ordering, check the exact Synology compatibility list for the system and any expansion shelf. Also confirm firmware update support through DSM, because first-party drive integration is one of the reasons to buy HAS rather than a generic SAS enterprise disk.
SAS drives can cost more and may have thinner retail availability than SATA drives. That is acceptable when the architecture needs SAS. It is wasteful when the architecture cannot use it.
At 24TB, an eight-drive SAS pool is 192TB raw and a 24-drive shelf is 576TB raw before protection and overhead. Stock spares by interface. A HAT5320 SATA spare does not replace a failed HAS5320 SAS drive in a SAS-only system, and the reverse is not a safe assumption either.
Avoid HAS5320 if the storage system has SATA-only bays, if the vendor compatibility page lists HAT but not HAS, or if the buyer is simply assuming SAS is the premium version of the same disk. It is a different interface for a different host design.
For most DiskStation and small-office Synology systems, HAT5320-24T is the relevant first-party 24TB drive. For third-party servers, compare normal SAS enterprise drives on qualification and price rather than paying for Synology integration that the host cannot use.
HAS5320-24T is Synology's 24TB 3.5-inch enterprise SAS hard drive.
Only if that exact system is SAS-capable and lists the model. Ordinary SATA DiskStation bays should use SATA drives such as HAT5320, not HAS5320.
The interface is different, but Synology lists 309MB/s typical maximum sustained transfer speed for both 24TB models. SAS is mainly about enterprise pathing and controller architecture.
Yes. A SAS drive requires SAS-capable controller and backplane support.
No. Price per TB is the first screen, not the whole decision. Match recording method, interface, bay count, firmware support, warranty position and rebuild risk before accepting the cheapest row.
Specification claims on this page were checked against the pages below on 1 September 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.