On 11/08/2016 02:38 PM, Phil Turmel wrote: > On 11/08/2016 02:53 PM, Benjammin2068 wrote: >> On 11/08/2016 12:47 PM, Benjammin2068 wrote: >> Now that I think about it -- and have been talking out loud to myself (I don't think I'm crazy)... >> >> A parallel to all this is: >> >> I don't think the mismatch_cnt started showing up until I moved from RAID5 to RAID6. >> >> :O >> >> How painful is it to switch back to RAID5 to test that theory? > Don't. Sounds like raid6's stricter calculations are catching a real problem. Ok -- no switching back to RAID5. > Do you have ECC RAM? Yes. > > If so, are you getting any machine check exceptions? not getting any machine check problems (I looked) > If not, have you done a thorough memtest any time in the recent past? Yes. When I started getting the mismatch counts, I took the system down and ran MEMtest on this through a couple of passes. no problem. > If it's not memory, can you exercise the controller channels heavily to > see if they drop from errors? I could but haven't -- any recommendations on tools out there? Also, I've also wondered if the raid-check that happens on Sunday isn't actually part of that kind of problem. i.e. if I didn't do the weekly check, the drives don't get slammed anywhere near as much the rest of the week. Does mismatch_cnt only change value during a check -- or does it happen with each operation? > Have you added up the peak current draws of your drives to make sure > your power supply keeps up when all drives are writing simultaneously > (common with parity raid)? Not exactly. but can do that. The system has a 650W supply -- I'll go do a power check and work that against the known drives in the system. This is a "server chassis" though which came with the 8 slots in the front to power drives - so it's not exactly a "home chassis" that I put in a 300W and then jammed full of drives. Still -- that's a reasonable question and I'll investigate. > One more: do you have swap on top of md raid? No. I've seen about mismatch on RAID1 causing mismatch counts. However, I am running a VM on this RAID volume (VirtualBox and a reasonably sleepy instance of Win7_64) and have pondered that. -Ben -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
