When is a SMART failure not an impending disk failure?

My old TrueNAS has been playing up.  It dropped a drive, rebooted, found its old mate, and resilvered it but afterwards still had errors:

  1. One or more devices has experienced an unrecoverable error.
  2. Pool state is DEGRADED: One or more devices are faulted in response to persistent errors.
  3. Disk ATA WDC WD40EFRX-68N is FAULTED
  4. The system had an unscheduled system reboot.
  5. Pool state is ONLINE: One or more devices is currently being resilvered.
  6. Pool state is ONLINE: One or more devices has experienced an unrecoverable error.

A few years back my Intel “server grade” motherboard died 6 months out of warranty and Intel were spectacularly unhelpful about it.  Gumtree to the rescue with a second hand AMD Phenom CPU and motherboard, at least 10 years old when I bought it and ran beautifully for another 2+ years.  However, the reboots are getting a little bit more often so it’s finally getting a bit long in the tooth.  Plus, a dodgy drive most likely?

Time to build a new NAS.  No point screwing about, AMD Ryzen 5 3600, ASRock x570 motherboard, 16GB ECC, 4U rackmount case, 10 hotswap bays, treat yo’self!

I also bought 5 x used 4TB SAS drives for a new TrueNAS build, seller seemed reputable enough.  Worth a gamble on cheap storage.  I already had an HBA that will let me use up to 8 SATA or SAS drives in addition to the 6 x SATA connectors on the motherboard.

First used drive I plugged in, passes SMART short test and fails SMART long test after only a couple of minutes (it should take 10 hours to complete).  Consistently.  On the same LBA.  Uh oh.

Well, fine.  Let’s be doubly sure.  Badblocks will surely tell me just how ruined this drive is.  Load it up with 5 passes (random, 0x55, 0xaa, 0xff, 0x00).  That’ll show me media errors.  Fast forward 5 days.  No errors.

Run SMART long again.  No errors.

So..  this drive obviously had something Really Bad(tm) on one of the sectors.  But NOT a drive problem.  Maybe power got pulled during a write or something, who knows.  But it’s fixed, I can’t fault it.  5 passes of badblocks and a followup SMART long are perfect.  SMART also reports 0 elements in grown defect list (which is the measure SAS drives use instead of reallocated sectors in SATA land).

 

 

 

 

 

I trust this drive, it’s had 5 passes of badblocks with no errors and passed SMART long test twice and it is recording no defects on the media.  SMART can be dumb sometimes!

 

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Space antenna!

Late in 2019 I heard of an upcoming project by SpaceAustralia to home brew your own radio-telescope, with the objective of peering at the Milky Way. Previously only the domain of scientists with very nice radio dishes, the reducing cost of entry has now put it in range of the hobbyist so it seemed like a cool thing to try.

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Saving the planet 3 batteries at a time

Sometimes little wins give you disproportionate satisfaction.

I bought a battery-powered LED light from a local hardware store. It cost 10 bucks and is surprisingly decent quality, using 3 x AAAs. Pushing the front bezel turns it on, pushing it again turns it off. I bought it for the enclave under the stairs where the wine lives. Problem is, I was confident that at some stage we’d would forget to turn it off again and come back to a non-functional light. That happened ahead of schedule, the first batteries lasted about a week. Righto then, we’ll fix that.

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Don’t buy garbage

I often hear expectations on what electronics “should” cost being set based on the cheapest price available on Ebay, Aliexpress et al.  Everybody loves a bargain, but the old saying “you get what you pay for” is just as true as ever.  What worries me is that by paying for junk, rather than quality, consumers are voting with their wallets for an inferior technological future.

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Taming the rPi Touchscreen PCB

After my last article‘s mission of discovery I set about trying to stop the rPi Official 7″ Touchscreen from interfering with my 2-way radio.  It looked like the LCD ribbon cable was broadcasting spurs every ~1MHz or so right through the VHF range.  I acquired some adhesive copper tape thinking I could shield the cable to prevent the noise from escaping.

The copper tape arrived, and despite wrapping the LCD ribbon cable and grounding the copper tape it failed to provide any shielding benefit.  Nuts.  So what else can I try?

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Raspberry Pi Car Shield

Raspberry Pi 2 + Power supply PCB + 7″ TFT

I’ve had an aftermarket ECU (Adaptronic) in my car for a little while now, and I wanted some extra dash gauges.  My car (Nissan R34 GTT) has a spot on the dashboard perfect for a 7″ TFT.  Raspberry Pi is the obvious choice, However, you can’t just run a Pi directly off the accessory power in a car.  Aside from voltage conversion, graceful shutdown is also mandatory!

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Raspberry Pi Webcam (Fishcam)

One day I was looking at my fishtank and thought it would be nice to see my fish behaving naturally.  The problem with sitting in front of the tank is they recognise someone is there and go into their “feeding” pattern – rising to the top of the tank in expectation of food.

If I added a webcam, I could push my  RPi temperature display into service.  As a bonus, I could measure the temperature of the tank at the same time.

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