Are refurbished enterprise hard drives worth it once the warranty and the failure risk are counted?

1. 1.Start from what an annualised failure rate measures. Backblaze's published query computes AFR as 100 x 365 x failures / drive-days, so an AFR of A% means A failures per 100 drive-years of running. Its own lifetime row for the Seagate ST16000NM001G reproduces it: 876 failures over 47,227,179 drive days is 876 / (47,227,179 / 365) x 100 = 0.68%.
2. 2.Choose the AFR input knowingly. In Backblaze's Q2 2026 Drive Stats (Stephanie Doyle, 29 September 2026) the fleet's quarterly AFR was 1.73% and its lifetime AFR 1.41%. Lifetime rates by model include 0.54% (WDC WUH721414ALE6L4, 14TB), 0.68% (Seagate ST16000NM001G, 16TB), 3.28% (ST10000NM0086, 10TB) and 5.88% (ST14000NM0138, 14TB); the lowest lifetime rate in the Q2 2026 table is 0.50% (Toshiba MG11ACA24TE).
   ReadingThese figures describe drives in Backblaze's own fleet. The Q2 2026 post we read does not mention refurbished or recertified drives, and we found no document giving a fleet statistic for refurbished drives as a class. Use your model's own row where Backblaze lists it, and run the sum at more than one AFR: in the same fleet the highest model rate above is more than ten times the lowest.
3. 3.Know what the rate counts and how it moves with age. A failure in Drive Stats is a drive leaving the reporting population, not a SMART value crossing a threshold. Backblaze describes the bathtub curve's three sections (decreasing, constant and increasing failure rate), but its 2025 review calls the curve incomplete: in 2025 its fleet's AFR peaked at 4.25% at 10 years 3 months of age.
4. 4.Work out usable capacity. OpenZFS gives a RAIDZ group of N drives of size X with P parity drives approximately (N - P) x X; raidz1, raidz2 and raidz3 survive one, two and three drive failures without losing data.
   ReadingSix 16TB drives in raidz2: (6 - 2) x 16 = 64TB, before the sector-size and record-size overhead that OpenZFS says makes real usable space lower.
5. 5.Count expected replacements: R = N x (AFR / 100) x Y for N drives over Y years. Split R at the warranty length W: a replacement inside W costs the claim and shipping, one after it costs a whole drive. In one TrueNAS thread a poster had three RMAs in a few months on refurbished MDD drives; replies split between buying new or manufacturer-recertified and spending the saving on cold spares, and buying used after a SMART check.
   ReadingSix drives at the 1.41% fleet lifetime AFR over 5 years: 6 x 0.0141 x 5 = 0.42 expected replacements. 1.41% is Backblaze's fleet figure used as an example input, not a rate for used drives. With a six-month warranty (W = 0.5) about a tenth of those fall inside it. The sum is linear and ignores a replacement failing in turn, which is acceptable at rates this small.
6. 6.Put it together for each offer: cost per usable TB-year = [N x C + R_in x claim cost + R_out x C] / [(N - P) x T x Y], where C is that offer's price (the list below shows used offers; take the new price from the same drive's new listing), T its capacity in TB, R_in = N x (AFR / 100) x W and R_out = N x (AFR / 100) x (Y - W). Run it for the used offer and for the same drive new, each with its own price and warranty.
   ReadingThen hold the new drive's AFR at your chosen figure and raise the used drive's AFR until the two costs meet. That break-even AFR is the rate the used drive has to beat; we found no document that tells you whether it will.

1. 1.Read the drive's identity as soon as it arrives.

   smartctl -i /dev/sdX

   ReadingModel, Serial Number and Firmware Version. Compare the reported model with the listing. Seagate lists its factory-recertified drives under part numbers ending NM000C or NM002C, each with a '6-month limited warranty', so check that the listing carries one; we found no document stating what smartctl -i reports for such a drive.
2. 2.Enter the serial at the maker's lookup. Seagate checks warranty status by serial number, and Seagate's statement on the 2025 fraud cases, as published by heise online, points buyers who doubt a seller's description to that warranty checker.
   ReadingThe result says whose warranty you hold. Seagate's recertified drives carry six months from Seagate; WD's recertified store states a 1-year limited warranty from Western Digital. A longer term on a listing is the seller's promise: in one ServeTheHome deal thread, Seagate's lookup showed no coverage for the serials of 'manufacturer recertified' drives sold with a 2-year limited warranty.
3. 3.Check for an OEM part number on an ex-server Seagate drive. Seagate's warranty on drives it sells to OEM customers runs from its shipment to that customer and extends only to that customer, not assignable or transferable without Seagate's consent; any warranty to end users is from the customer, not from Seagate.
   ReadingSuch a drive may show no coverage at Seagate's lookup. Price it with the warranty the listing or seller states, or with none. We found no equivalent WD or Toshiba document.

1. 1.Read the ATA attribute table and note the RAW_VALUE column.

   smartctl -A /dev/sdX

   ReadingID 9 Power_On_Hours counts hours powered on; Seagate's openSeaChest wiki notes that on a hard drive this is not the same as hours the spindle has been spinning. Note IDs 5, 187, 188, 197 and 198 as well, for the test path below.
2. 2.Compare it with the self-test log, which is a separate record.

   smartctl -l selftest /dev/sdX

   ReadingThe LifeTime(hours) column records the disk-lifetime hour at which each of the last 21 self-tests (ATA) ran. An entry above the current Power_On_Hours means the power-on counter does not describe this drive's history: return it inside the window. A 2015 ServeTheHome thread reports exactly this on a drive sold as new, with near-zero Power_On_Hours and tests logged at 9,607 and 6,072 hours.
3. 3.On a Seagate SATA or SAS drive, read the FARM log too. It needs smartctl 7.4 or later, the man page marks the feature experimental, some Seagate drives do not support it, and the ATA and SAS logs differ.

   smartctl -l farm /dev/sdX

   ReadingFARM's General Drive Information carries its own Power On Hours, Spindle Power On Hours and Head Flight Hours. Compare FARM Power On Hours with SMART ID 9: a large disagreement means one of the two records does not reflect the drive's use. We found no Seagate document stating that FARM cannot be reset, so agreement is consistent, not proof.
4. 4.On a SAS drive, read the full output instead, because SAS drives do not present the ATA attribute table.

   smartctl -x /dev/sdX

   Reading-x prints all SMART and non-SMART information. The documents we read define no thresholds for the SAS fields (accumulated power-on time, grown defect list), so record them as printed. We found no smartctl document stating that the SCSI self-test log records lifetime hours; compare whatever the log prints.

1. 1.Read the overall health verdict. In one 2026 TrueNAS thread, the eBay replacement bought for a failed Amazon renewed drive reported FAILED here.

   smartctl -H /dev/sdX

   Reading'SMART overall-health self-assessment test result: FAILED' is a reject. The man page says a failing health status means the device has already failed or is predicting its own failure within the next 24 hours. PASSED does not clear a drive on its own.
2. 2.Look again at the five counters from the attribute table: IDs 5 (Reallocated_Sector_Ct), 187 (Reported_Uncorrect), 188 (Command_Timeout), 197 (Current_Pending_Sector) and 198 (Offline_Uncorrectable).
   ReadingIn Backblaze's 2016 analysis, 76.7% of failed drives and 4.2% of operational drives had one or more of these above zero, and 23.3% of failed drives showed nothing in them. The openSeaChest wiki page we read gives no acceptable reallocated count, so a non-zero value is a reason to look harder and a value that grows during your tests is a reason to return the drive.
3. 3.Run the extended self-test, which takes tens of minutes to several hours, and read the self-test log when it finishes.

   smartctl -t long /dev/sdX

   ReadingThen smartctl -l selftest /dev/sdX: 'Completed without error' is the pass; 'Completed: read failure' with an LBA_of_first_error is a reject inside the return window.
4. 4.Empty drive only, not yet in a pool: this write test erases every block, and anything on the drive is lost. badblocks -w writes the patterns 0xaa, 0x55, 0xff and 0x00 to every block and reads each back, and its man page says never to use -w on a device containing an existing file system. badblocks counts in 1024-byte blocks by default and refuses an end block that does not fit in 32 bits, so set -b so that the drive's capacity divided by the block size stays below 2^32: -b 4096 up to 16 TiB, -b 8192 above. Check the device name twice. Replies in a Level1Techs thread give the same advice in general terms: burn in and test a refurbished drive before trusting it.
   Destructive. This command destroys what is on the device and cannot be undone. Confirm the device path twice and have a backup of anything you still need before running it.

   badblocks -wsv -b 4096 /dev/sdX

   Reading-s shows progress and -v reports read, write and corruption error counts; any non-zero count is a reject. Afterwards run smartctl -A again and see whether IDs 5, 197 or 198 moved.

We found no document with a fleet statistic that answers this for refurbished drives. Backblaze's 2025 review of its own fleet says drives aged zero to one year 'barely crack 1.30% AFR', and its 2021 post found that early, decreasing-failure-rate section dramatically lower than in 2013, when it was 5.1% over 0 to 18 months. Those figures are by age in Backblaze's fleet; Seagate's own footnote calls its recertified products 'used, reconditioned, or repurposed', so a recertified drive's first year with you is not its first year of use.

Backblaze counts a failure when a drive leaves its reporting population, not when a SMART value crosses a threshold. In its 2016 analysis, 4.2% of operational drives had one or more of the five stats it tracked above zero, against 76.7% of failed drives, and 23.3% of failed drives showed no warning in them, so all-zero counters do not rule a failure out.

Only as much as that seller's promise. Replies in a 2024 TrueNAS thread cite seller warranties of two to five years, and in a ServeTheHome thread Seagate's lookup showed no coverage for drives a seller sold as manufacturer recertified with a 2-year warranty. In the cost formula, count a seller's term as warranty only for as long as you expect that seller to be there to honour it.

For a Seagate factory-recertified drive (part number ending NM000C or NM002C) whose serial Seagate's lookup covers, set W to the coverage the lookup shows remaining, at most 0.5 years and price a replacement inside it at your claim and shipping cost; for a drive bought from WD's recertified store, W = 1. For an offer whose only warranty is the seller's, W is the term the listing states, and a replacement inside it costs whatever claiming from that seller costs you; if the listing states none, or the serial lookup shows no maker coverage and you would not rely on the seller, set W = 0 so every expected replacement is priced at a full drive. Seagate's recertified part numbers and programme are set out on /resellers/manufacturer-recertified.