I have two enterprise-grade SSDs that I've been using for L2ARC in an OpenZFS pool for a few years. Workflow during this time has been fairly heavy, with lots of reads and writes, serving up video to clients for video post-production.

Recently, got a couple of critical alerts about the L2ARC SSDs:

CRITICAL: Oct. 22, 2018, 6:12 p.m. - Device: /dev/da0 [SAT], 215869351264256 Offline uncorrectable sectors
CRITICAL: Oct. 22, 2018, 6:12 p.m. - Device: /dev/da1 [SAT], 174264003067904 Offline uncorrectable sectors

Obviously there's no risk of data loss, since these are just L2ARC, but is it time to just get them replaced?

Am I sacrificing performance? If not, is there a way to reset or ignore the bad sectors?

Using FreeNAS-11.1-U6.


Those numbers are obviously bogus. Your SSD doesn't have that many sectors at all, let alone offline uncorrectable ones. Check for firmware updates for your SSD that will fix the problem. Otherwise, ignore it. If you're really paranoid, you could replace the drives, but in that case you should use different drives, not the same brand from the same manufacturer (because they obviously have faulty firmware).

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    Those numbers are both 48 bits, where the lower 32 bits are all zero. So while a firmware update is a fine thing to check for, it might also just be the (unspecified) drive manufacturer putting something into / structuring that SMART field in a way which FreeNAS' tools aren't expecting. – Jay Kominek Oct 23 '18 at 22:01
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    @JayKominek That's a very good point. It may well be some vendor-specific absurdity that smartmontools isn't aware of yet. But vendors are going to keep doing crazy things like this until their customers complain and take their business elsewhere. – Michael Hampton Oct 23 '18 at 22:09
  • Related Q: could this possibly be affecting read performance? I’m finding that mere playback of video is stuttering across even just two clients. I had no issues before this serving up video to 8 clients. – user260467 Oct 23 '18 at 23:45
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    @user260467 It could be. Your SSDs could actually be defective, or counterfeit, or something else. You shared virtually no information about them, so anything would be speculation at this point. – Michael Hampton Oct 24 '18 at 0:22
  • @MichaelHampton The drives are two of these, 400GB. Still under warranty so I’m RMAing them. eshop.macsales.com/shop/SSD/OWC/Mercury_6G/Enterprise – user260467 Oct 24 '18 at 1:30

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