This is just trying to read 5GB off the drive with dd and the drive initially tested ok but shortly after I wondered why I was seeing 2MB/s read speeds. Notice the "current_pending_sector", anytime I've seen it at anything above 0 even with no other bad fields/attributes, it means the drive is bad.
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:00:00:8b:34/01:00:00:00:00/40 tag 0 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:08:00:8b:34/01:00:00:00:00/40 tag 1 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:00:00:8b:34/01:00:00:00:00/40 tag 0 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:08:00:8b:34/01:00:00:00:00/40 tag 1 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:00:00:8b:34/01:00:00:00:00/40 tag 0 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/00:08:00:8b:34/01:00:00:00:00/40 tag 1 ncq 131072 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
sd 0:0:0:0: [sda] Unhandled sense code
sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 0:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor]
Descriptor sense data with sense descriptors (in hex):
72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
00 34 8b c8
sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed
sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 34 8b 00 00 01 00 00
Buffer I/O error on device sda, logical block 430457
Buffer I/O error on device sda, logical block 430458
Buffer I/O error on device sda, logical block 430459
Buffer I/O error on device sda, logical block 430460
Buffer I/O error on device sda, logical block 430461
Buffer I/O error on device sda, logical block 430462
Buffer I/O error on device sda, logical block 430463
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:08:c8:8b:34/00:00:00:00:00/40 tag 1 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
ata1: EH complete
ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0
ata1.00: irq_stat 0x40000008
ata1.00: failed command: READ FPDMA QUEUED
ata1.00: cmd 60/08:00:c8:8b:34/00:00:00:00:00/40 tag 0 ncq 4096 in
res 41/40:00:c8:8b:34/00:00:00:00:00/40 Emask 0x409 (media error) <F>
ata1.00: status: { DRDY ERR }
ata1.00: error: { UNC }
ata1.00: configured for UDMA/133
sd 0:0:0:0: [sda] Unhandled sense code
sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 0:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor]
Descriptor sense data with sense descriptors (in hex):
72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
00 34 8b c8
sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed
sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 34 8b c8 00 00 08 00
Buffer I/O error on device sda, logical block 430457
ata1: EH complete
smartctl -a /dev/sda
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-2.6.32-279.el6.x86_64] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net
=== START OF INFORMATION SECTION ===
Model Family: Western Digital Caviar Green (Adv. Format)
Device Model: WDC WD20EARX-008FB0
Serial Number: WD-WCAZAK523299
LU WWN Device Id: 5 0014ee 25d303568
Firmware Version: 51.0AB51
User Capacity: 2,000,398,934,016 bytes [2.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Thu May 16 04:36:59 2013 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 331) minutes.
Conveyance self-test routine
recommended polling time: ( 5) minutes.
SCT capabilities: (0x30b5) SCT Status supported.
SCT Feature Control supported.
SCT Data Table supported.
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 18
3 Spin_Up_Time 0x0027 100 253 021 Pre-fail Always - 0
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 2
5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 685
10 Spin_Retry_Count 0x0032 100 253 000 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 253 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 2
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 1
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 32
194 Temperature_Celsius 0x0022 123 121 000 Old_age Always - 27
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 3
198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 100 253 000 Old_age Offline - 0
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Extended offline Interrupted (host reset) 90% 134 -
SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.
wd, earx, tb, daysthis, gb, dd, initially, ok, mb, speeds, quot, current_pending_sector, ve, fields, attributes, ata, exception, emask, sact, serr, irq_stat, fpdma, queued, cmd, ncq, res, drdy, err, unc, configured, udma, sda, unhandled, hostbyte, did_ok, driverbyte, driver_sense, medium, descriptor, descriptors, hex, unrecovered, auto, reallocate, cdb, buffer, smartctl, dev, _, linux, copyright, allen, http, smartmontools, sourceforge, western, digital, caviar, adv, format, wdc, fb, wcazak, lu, wwn, ee, firmware, ab, user, capacity, bytes, sector, sizes, database, specification, draft, indicated, thu, edt, capability, enabled, offline, suspend, scan, supported, conveyance, selective, capabilities, saves, mode, supports, timer, logging, recommended, polling, extended, sct, feature, revision, vendor, thresholds, attribute_name, thresh, updated, when_failed, raw_value, raw_read_error_rate, spin_up_time, start_stop_count, old_age, reallocated_sector_ct, seek_error_rate, power_on_hours, spin_retry_count, calibration_retry_count, power_cycle_count, off_retract_count, load_cycle_count, temperature_celsius, reallocated_event_count, offline_uncorrectable, udma_crc_error_count, multi_zone_error_rate, errors, logged, num, test_description, remaining, lba_of_first_error, interrupted, reset, span, min_lba, max_lba, current_test_status, not_testing, flags, scanning, selected, spans, remainder, disk, pending, resume,