LCC and drive durability

[Decto]

Hi,

 

TL:DR My drives have LCC of 1.5m and 850k vs data sheet 300k. Is this really an issue?

 

I reconfigured my unraid around 2 years ago with new and repurposed drives and then about 12 months ago added a second parity and second SSD for cache.

It's pretty much been left to its' own devices save periodic OS updates and adding more dockers. Over this holiday period I swapped both 4TB parity drives for 8TB.

 

While looking in the smart logs, I see the the 3TB Green WD30-EZRX has and LCC of almost 1.5m and a shucked 4TB from early 2019, I suspect a white labeled blue WD40-EMAZ has an LCC of almost 850k. Both of these drives are speced at max LCC of 300k and the smart data shows 001 (starts at 200)

Neither drive has ever flagged a read error or a SMART error.

 

Turns out my docker and libvirt images were on drive 1 (WD green) and the writes were happening constantly, but not constantly enough to stop the heads parking every 8 seconds. The parity drives were a 4TB Red (still low LCC)  and the shucked blue which also must be parking at 8 sec. I've now moved the files to the cache and my array now spins down fully when not in use. I updated parking to 300s on the Green drive, however none of the tools worked on the blue so I have that to figure out yet.

 

So the question is, is the high LCC count still a significant risk to the drive integrity?

 

The 4TB blue? is now unassigned. I've now run a full pre read / zero / post read, pre-clear cycle and an extended smart diagnostics,  SMART data is still good, not a single replaced sector, all paramters normal except the super high LCC. Currently this is out of the array as I'm pre-clearing another 8TB I shucked.

 

The 3TB green is still in service, with 4TB Red pre-cleared  and on standby. Again the 3TB has no smart errors/ warnings or replaced sectors despite the 1.5m LCC. Once the 8TB is cleared, I could replace it with the 4TB red which would allow me to test it out.

 

While the safest option may be to repurpose these drives for something else, is this LCC really such an issue, or just what was tested in the validation. Early drives with high LCC had known elevated failure rates, however given the Green is at 1.5m it gives me some confidence I should get similar mileage from the blue and both drives so no signs of issues at this point so it seems a shame not to use them. Even the Green isn't likely to increase the LCC much now it's fixed.

 

Anyone have experience of running drives with such high LCC ?

 

Topic posted as while I can see lots post concerned with LCC, I can't find any on whether there were real consequences or examples of people running them with high LCC.

Edited January 2, 2020 by Decto
clarity