One of my disks went out to lunch for a while. Logs below. Which one is it? The only useful thing in /sys/class/ata_port/ata4 is the device symlink, which points at /sys/devices/pci0000:00/0000:00:1f.2/ata4. That, in turn, has an ata_port directory (contains nothing I don't already know) and a link4 directory. The ata_link directory is unhelpful, as is /sys/devices/pci0000:00/0000:00:1f.2/ata4/link4/dev4.0/ata_device/dev4.0. Taking a leap of faith, /sys/devices/pci0000:00/0000:00:1f.2 contains ata1-6 and host0-5. So maybe ata4 is host3. Following lots of symlinks through host3 leads me to the block device sdd. Maybe that's correct? I'm really not sure. Am I missing something obvious? I even tried looking for symlinks the other way, like this: /sys$ find -type l -exec echo -n {} ' ' \; -exec readlink {} \; |grep ata4 ./devices/pci0000:00/0000:00:1f.2/ata4/ata_port/ata4/subsystem ../../../../../../class/ata_port ./devices/pci0000:00/0000:00:1f.2/ata4/ata_port/ata4/device ../../../ata4 ./devices/pci0000:00/0000:00:1f.2/ata4/link4/ata_link/link4/subsystem ../../../../../../../class/ata_link ./devices/pci0000:00/0000:00:1f.2/ata4/link4/ata_link/link4/device ../../../link4 ./devices/pci0000:00/0000:00:1f.2/ata4/link4/dev4.0/ata_device/dev4.0/subsystem ../../../../../../../../class/ata_device ./devices/pci0000:00/0000:00:1f.2/ata4/link4/dev4.0/ata_device/dev4.0/device ../../../dev4.0 ./class/ata_link/link4 ../../devices/pci0000:00/0000:00:1f.2/ata4/link4/ata_link/link4 ./class/ata_port/ata4 ../../devices/pci0000:00/0000:00:1f.2/ata4/ata_port/ata4 ./class/ata_device/dev4.0 ../../devices/pci0000:00/0000:00:1f.2/ata4/link4/dev4.0/ata_device/dev4.0 No luck. [784786.047673] ata4.00: exception Emask 0x10 SAct 0x7800 SErr 0x0 action 0x6 frozen [784786.047707] ata4.00: irq_stat 0x08000000, interface fatal error [784786.047730] ata4.00: failed command: READ FPDMA QUEUED [784786.047752] ata4.00: cmd 60/40:58:80:a9:48/00:00:86:00:00/40 tag 11 ncq 32768 in [784786.047753] res c0/00:40:80:15:8d/00:00:86:00:00/40 Emask 0x12 (ATA bus error) [784786.047805] ata4.00: status: { Busy } [784786.047819] ata4.00: failed command: READ FPDMA QUEUED [784786.047840] ata4.00: cmd 60/40:60:80:aa:48/00:00:86:00:00/40 tag 12 ncq 32768 in [784786.047841] res c0/00:40:80:15:8d/00:00:86:00:00/40 Emask 0x12 (ATA bus error) [784786.047893] ata4.00: status: { Busy } [784786.047907] ata4.00: failed command: READ FPDMA QUEUED [784786.047928] ata4.00: cmd 60/40:68:c0:aa:48/00:00:86:00:00/40 tag 13 ncq 32768 in [784786.047929] res c0/00:40:80:15:8d/00:00:86:00:00/40 Emask 0x12 (ATA bus error) [784786.047981] ata4.00: status: { Busy } [784786.047996] ata4.00: failed command: READ FPDMA QUEUED [784786.048016] ata4.00: cmd 60/40:70:00:ab:48/00:00:86:00:00/40 tag 14 ncq 32768 in [784786.048017] res c0/00:40:80:15:8d/00:00:86:00:00/40 Emask 0x12 (ATA bus error) [784786.048067] ata4.00: status: { Busy } [784786.048085] ata4: hard resetting link [784786.365119] ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [784786.380854] ata4.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded [784786.380860] ata4.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out [784786.380864] ata4.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out [784786.382279] ata4.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded [784786.382283] ata4.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out [784786.382287] ata4.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out [784786.382747] ata4.00: configured for UDMA/133 [784786.382761] ata4: EH complete --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html