On 9 May 2017, Tim Small spake thusly: > On 09/05/17 11:40, Nix wrote: >> I've had disk failures without warning, and >> non-failed disks with both read and write errors that would not go away, >> but that SMART reallocation value just stayed stuck at zero through all >> of it. > > Really? I see them pretty frequently... Let's see > > server1, RAID6 (4 disks), reallocated_sector_ct: 0 9 1 0 > server2, RAID5 (4 disks), reallocated_sector_ct: 0 0 0 0 > server3, RAID6 (5 disks), reallocated_sector_ct: 34 754 15 115 1 > server4, RAID5 (4 disks), reallocated_sector_ct: 0 0 0 0 > server5, RAID5 (4 disks), reallocated_sector_ct: 0 0 0 0 > > Disk 2 in server3 (which has drives which are a bit long in the tooth) > is scheduled to be replaced next time I visit that site. > > Are you looking at the 'raw' column in the smartctl output? No, but since they all read all zero: 5 Reallocated_Sector_Ct PO--CK 100 100 010 - 0 this is pretty redundant. I do see, on all my disks (regardless of hardware versus software RAID or indeed age, and some of these disks are seven years old): 196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0 197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0 200 Multi_Zone_Error_Rate 0x0008 200 200 051 Old_age Offline - 0 One figure is much higher: 195 Hardware_ECC_Recovered -O-RC- 100 064 000 - 2067212 195 Hardware_ECC_Recovered -O-RC- 100 064 000 - 2088928 195 Hardware_ECC_Recovered -O-RC- 082 064 000 - 156528817 195 Hardware_ECC_Recovered -O-RC- 082 065 000 - 156513792 but this is on a bunch of three-month-old Seagate enterprise disks, and as with the seek error rate Seagate use a deeply bizarre encoding for this value, and none of the SeaChest programs seem to be able to decode it. It appears that the lower the decoded value, the worse things are -- I have no idea why two of my drives are doing so much worse than two others on this score. I guess I should keep an eye on them. In any case, it's going up fast on those two even when the drives are totally idle and even when I forcibly spin them down... I don't trust this figure to tell me anything useful at all. SMART, borderline useless as ever. Aside: in hex these are 001f8b0c 001fdfe0 095470b1 09543600 which rather suggests that the drives have two distinct encodings to me, with two drives using one encoding and the other two another one, probably split at the four-hex-digit mark -- but the drives have identical firmware and the same model number... -- 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
