Synology 5bay Expansion Unit DX517 157 mm drops to $523.05

$18.82 off right now.

Expanding a Synology NAS is the fastest way to add storage without migrating to a whole new unit, and the DX517 is the accessory built exactly for that job. Amazon has it at $523.05 for the 5-bay expansion chassis. That is $18.82 below the recent going rate, so if you have been planning to grow your DiskStation. This is the moment to lock it in. The saving is modest, but expansion units rarely move much at all, and this one has been sitting at roughly $541.87 across the last 30, 90, and 180 days. For just $523.05, below its 30-day average of $541.87, you are paying less than the usual price for a component you will likely run for years.

THE DEAL

Synology 5bay Expansion Unit DX517 157 mm

$523.05 (was $541.87) - Save $18.82 (3% off)

WhereAmazon

ExpiresNo end date listed

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What You're Getting

The DX517 adds five extra drive bays to a compatible Synology DiskStation, turning a two-bay unit into a seven-bay setup without buying a new NAS. Both 2.5-inch and 3.5-inch SATA drives fit, and the hot-swappable trays make drive swaps quick and tool-free.

Run it as a separate volume and it doubles as a dedicated local backup target that keeps your primary disks isolated from a system failure. Check Synology's compatibility list before you buy to confirm your model supports it.

Who This Is For

Best for anyone running out of bays on an existing Synology NAS who wants more capacity without the cost and migration hassle of trading up to a larger chassis. It also suits users who want a physically separate backup volume on the same box.

If your storage needs are still small or you are planning a full NAS upgrade soon, you can hold off.

The Caveat

Keep in mind that the DX517 has no standalone processing power, so it depends entirely on the host DiskStation. It also sits well above its all-time low of $407.99, so if you are not in a hurry, waiting for a deeper cut is an option. For anyone needing capacity now, the current price is fair.

Final Verdict

If your NAS is full and you want the cheapest path to five more bays, $523.05 gets the job done. The discount is small, but expansion units rarely go on sale at all, so this is a reasonable price to bite on if you need the space today.