From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Shanahan Subject: Read errors and SMART tests Date: Sat, 20 Dec 2008 12:00:44 +1030 Message-ID: <20081220013043.GM1749@cubit> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, Just a quick question about SMART tests :- I have a Samsung drive returning read errors, e.g.: Dec 20 08:59:24 hermes kernel: ata4.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x0 Dec 20 08:59:24 hermes kernel: ata4.00: irq_stat 0x40000008 Dec 20 08:59:24 hermes kernel: ata4.00: cmd 60/80:00:3f:0e:50/00:00:24:00:00/40 tag 0 ncq 65536 in Dec 20 08:59:24 hermes kernel: res 41/40:00:61:0e:50/00:00:24:00:00/40 Emask 0x409 (media error) Dec 20 08:59:24 hermes kernel: ata4.00: status: { DRDY ERR } Dec 20 08:59:24 hermes kernel: ata4.00: error: { UNC } Dec 20 08:59:24 hermes kernel: ata4.00: configured for UDMA/133 Dec 20 08:59:24 hermes kernel: ata4: EH complete Dec 20 08:59:24 hermes kernel: sd 3:0:0:0: [sdd] 1953525168 512-byte hardware sectors (1000205 MB) Dec 20 08:59:24 hermes kernel: sd 3:0:0:0: [sdd] Write Protect is off Dec 20 08:59:24 hermes kernel: sd 3:0:0:0: [sdd] Mode Sense: 00 3a 00 00 Dec 20 08:59:24 hermes kernel: sd 3:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA So, I ran the short (and long) selftest and it showed read failures. Then I put in a new drive to replace it and ran the short selftest again - this one is showing read errors also: === START OF READ SMART DATA SECTION === SMART Self-test log structure revision number 0 Warning: ATA Specification requires self-test log structure revision number = 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Short offline Completed: read failure 20% 2572 294961 # 2 Short offline Aborted by host 20% 2572 - I'm guessing this is just bad luck, i.e. drives from the same bad batch. Erm, so my question - Am I right in assuming that the SMART self test is not influenced in any way by bad cables, etc.? If the drive returns read errors on it's self-test the error is within the drive itself, right? Thanks, Kevin.