A UPS for your NAS: sizing and Canadian picks
By Ryan Fournier · Reviewed by Claire Bergeron · Updated · Prices checked A NAS should sit on a UPS, because an unclean power cut during a write can corrupt a pool or a rebuild. For a typical four-bay NAS drawing 40 to 60 W, a 650 to 900 VA line-interactive UPS gives several minutes of runtime: enough for the NAS to see the outage over USB and shut down cleanly. Good Canadian picks are APC Back-UPS and CyberPower units, from roughly CA$110 to CA$200.
Why a NAS needs a UPS
RAID and ZFS protect against a drive failing, not against the power cutting out mid-write. An abrupt outage during a write (or worse, during a parity rebuild) can leave the array inconsistent or, on the wrong filesystem, corrupt. A UPS bridges the gap: it holds the NAS up long enough to flush writes and shut down in an orderly way.
The NAS talks to the UPS over USB. Synology, UGREEN, QNAP, TrueNAS and Unraid all read the UPS status and trigger a safe shutdown when the battery runs low: you set the threshold once.
Sizing: VA and runtime
APC UPS Battery Backup & Surge Protector with USB Charger, 600VA APC Back-UPS (BE600M1)You are not trying to run the NAS through a long outage, just to survive brief cuts and shut down cleanly on longer ones. For a four-bay NAS at 40 to 60 W, a 650 to 900 VA line-interactive unit gives roughly 5 to 15 minutes, which is ample. A six-bay or a NAS-plus-switch setup wants 900 to 1500 VA.
Choose line-interactive (it regulates minor sags without switching to battery) over a cheap standby unit, and check the unit has a USB port your NAS supports.
Setting up safe shutdown
- Connect the UPS to the NAS by USB.
- In the NAS settings, enable UPS support and set it to shut down when the battery is low (or after N minutes on battery).
- Test it once by pulling the UPS from the wall and confirming the NAS shuts down cleanly before the battery dies.
As an Amazon Associate we earn from qualifying purchases on Amazon.ca.
NAS drives on Amazon.ca by CA$/TB
Whichever model you choose, it needs CMR NAS drives rated for 24/7 use. These are the current best value per terabyte, live from Amazon.ca in Canadian dollars.
| Model | Capacity | Recording | Price | CA$/raw TB | |
|---|---|---|---|---|---|
 Western Digital 20TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD202KFGXNewbest price per TB CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon.ca · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$1,201Buy on Amazon | 20 TB | CMR ✓ | CA$1,201 | CA$60.03/TB | Buy on Amazon |
 Western Digital 22TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD221KFGXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026 · ships from the US through Amazon.caCA$1,452Buy on Amazon | 22 TB | CMR ✓ | CA$1,452 | CA$66.00/TB | Buy on Amazon |
 Western Digital 16TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 256 MB Cache, 3.5" - WD161KFGXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon.ca · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$1,060Buy on Amazon | 16 TB | CMR ✓ | CA$1,060 | CA$66.25/TB | Buy on Amazon |
 Seagate IronWolf Pro 14TB Enterprise NAS Internal HDD Hard Drive – CMR 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Cache for RAID Network Attached Storage, Rescue Services - FFP (ST14000NTZ01)New CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Deals2You · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$930Buy on Amazon | 14 TB | CMR ✓ | CA$930 | CA$66.43/TB | Buy on Amazon |
 Western Digital 12TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD122KFBXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026 · ships from the US through Amazon.caCA$815Buy on Amazon | 12 TB | CMR ✓ | CA$815 | CA$67.94/TB | Buy on Amazon |
 Western Digital 4TB WD Red Plus NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, CMR, 128 MB Cache, 3.5" - WD40EFZZNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon.ca · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$275Buy on Amazon | 4 TB | CMR ✓ | CA$275 | CA$68.75/TB | Buy on Amazon |
 HD 18TB N300 PRO NAS 3.5 in 7200RPM SATA III TOSHIBA HDWG81JXZSTBNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Canada Direct - Often Ships Same Day! · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$1,253Buy on Amazon | 18 TB | CMR ✓ | CA$1,253 | CA$69.61/TB | Buy on Amazon |
 Western Digital 3TB WD Red Plus NAS Internal Hard Drive HDD - 5400 RPM, SATA 6 Gb/s, CMR, 256 MB Cache, 3.5" -WD30EFPXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Generic Computer · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$210Buy on Amazon | 3 TB | CMR ✓ | CA$210 | CA$70.00/TB | Buy on Amazon |
 Seagate IRONWOLF 6TB NAS 3.5IN 6GB/S SATA 256MBNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Compute4Less Corp · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$423Buy on Amazon | 6 TB | CMR ✓ | CA$423 | CA$70.50/TB | Buy on Amazon |
 Western Digital 24TB WD Red Pro NAS Internal Hard Drive HDD - 7200 RPM, SATA 6 Gb/s, CMR, 512 MB Cache, 3.5" - WD241KFGXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026 · ships from the US through Amazon.caCA$1,697Buy on Amazon | 24 TB | CMR ✓ | CA$1,697 | CA$70.71/TB | Buy on Amazon |
 HD 14TB N300 PRO NAS 3.5 in 7200RPM SATA III TOSHIBA HDWG81EXZSTBNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Canada Direct - Often Ships Same Day! · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$992Buy on Amazon | 14 TB | CMR ✓ | CA$992 | CA$70.87/TB | Buy on Amazon |
 Toshiba N300 PRO 8TB Large-Sized Business NAS (up to 24 Bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/Year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG780XZSTBNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by OneDealOutlet Canada · one bare internal drive; shipping and taxes not included · checked Oct 15, 2026CA$572Buy on Amazon | 8 TB | CMR ✓ | CA$572 | CA$71.51/TB | Buy on Amazon |
Read more
Frequently asked questions
What size UPS for a NAS?
For a four-bay NAS at 40–60 W, a 650–900 VA line-interactive UPS gives several minutes: enough to shut down cleanly. Six-bay or NAS-plus-switch setups want 900–1500 VA. You are sizing for a clean shutdown, not to ride out a long outage.
Do I really need a UPS for a NAS?
Strongly recommended. RAID protects against a drive failing, not against power cutting out mid-write, which can corrupt a pool or a rebuild. A UPS plus USB safe-shutdown removes that risk cheaply.
Line-interactive or standby UPS?
Line-interactive. It regulates minor voltage sags without switching to battery, which is easier on the NAS and the battery than a cheap standby unit.
Ryan Fournier covers home-server hardware and efficiency at nasdrives.ca: the right power supply, the UPS, and what a NAS actually draws running around the clock, priced against Canadian hydro rates.
Reviewed by Claire Bergeron, Editor-in-chief