Dag-Erling Smørgrav wrote:

There is really only one error. The example from my e-mail is half a year old, but the disk is running fine from this time. The error occured at the initial gmirror sync. No more errors shown after rewriting the disk with zeros.

As you can see, there are really two different numbers LBA=79725056 in messages and LBA = 0x04c0826f = 79725167 in SMART log.

root@edith ~/# zcat /var/log/messages.3.bz2 | grep LBA

Sep 23 23:58:00 edith kernel: ad4: FAILURE - READ_DMA status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> LBA=79725056

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root@edith ~/# smartctl -l error /dev/ad4

smartctl version 5.38 [amd64-portbld-freebsd7.2] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/

=== START OF READ SMART DATA SECTION === SMART Error Log Version: 1 ATA Error Count: 1 CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days.

Error 1 occurred at disk power-on lifetime: 0 hours (0 days + 0 hours) When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 6f 82 c0 44 Error: UNC at LBA = 0x04c0826f = 79725167

Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 00 00 82 c0 44 00 25d+23:23:36.710 READ DMA c8 00 00 00 81 c0 44 00 25d+23:23:36.710 READ DMA c8 00 00 00 80 c0 44 00 25d+23:23:36.710 READ DMA c8 00 00 00 7f c0 44 00 25d+23:23:36.710 READ DMA c8 00 00 00 7e c0 44 00 25d+23:23:36.710 READ DMA