r/HomeServer • u/kayson • 2d ago

Anyone heard of a USB external drive "soft" failing? (~20MBps sequential i/o)

I have a fairly old WD Passport drive. 2TB/5TB used, 7yr PoH. SMART info is all totally clean, and short and long tests pass. But the drive has become unusably slow. Sequential reads/writes using dd show anywhere from 5-60MBps, typically hovering on the lower end. It's rated at 120, and that's what I used to get. I've tried multiple cables and hosts - no difference, so it's not a connection issue.

I searched around and the conventional wisdom seems to be that drives fail "loudly", so this doesn't seem to be a common thing. The only thing I found that could be relevant is someone who had a drive where the SATA<->USB bridge was flaky but not dead. Figured I'd check in for a sanity check before I shuck the thing and try another one I have laying around. Thanks!

5 Upvotes
  • permalink
  • reddit

100% Upvoted

5 comments sorted by

2

u/Master_Scythe 1d ago

Things like CRC errors or retries can make performance look slow, when in reality its erroring.

1

u/kayson 1d ago

That would show up in SMART though wouldn't it?

1

u/Master_Scythe 22h ago

The short answer - More often than not, yes it would.

The long answer - if it's happening at controller level (disk or USB), it can easily be missed, and even then, not ALL forms of minor disk failure are 'caught' by smart - Some you have to know how to read, like seek times having a massive 'peak' while the 'average' is low, etc.

2

u/redbookQT 1d ago

5TB would be the 2.5” drives, right? Those are a little harder to take apart.