On Sun, 28 Oct 2012 14:34:49 -0600 Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > A drive that can sit there like a bump on the log for 2 minutes before it issues an actual read failure on sector(s) means mdadm is likewise waiting, and everything above it is waiting. That's a long hang. I'd not be surprised to see users go for hard reset with such a system hang after 45 seconds let alone 2 minutes. Which is not different from what you would get (the same hang) in a non-RAID environment on the same drive, so I don't see how this would be specifically a RAID-related problem. > Anyway, the idea mdadm users can't benefit from shorter ERC is untrue. They certainly can. But the open question is why would they be getting such long error recovery times in the first place? 7 seconds is a long time. One thing is "benefit", i.e. just a comfort issue, to prevent pauses when a drive starts failing (but really... does that happen very often? and during those times do you really care so that there are no pauses for error recovery, or maybe you just want to replace the drive and still have your data safe?), and another thing is a complete RAID failure that you'd get with a hardware RAID controller simply because something is not within 7 seconds, which is the whole source of that vendor-supported myth of "non-RAID drives". -- With respect, Roman ~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Stallman had a printer, with code he could not see. So he began to tinker, and set the software free."
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