mdadm raid5 drive failure

[wheniwork]

I had a heat problem over the weekend with my MDADM RAID5. One of the drives supposedly failed.

I think the controller just shut the HD down and now MDADM thinks its failed.

How do I know for sure? Should I just do mdadm --assemble --force /dev/md0

Here is what SMART Tools gave me on the "failed" drive when scanned. Is it truly a dead drive?

I will post whatever info would help in determining what I should do. Reassemble array, replace the drive, etc?


smartctl version 5.37 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen
Home page is http://smartmontools.sourceforge.net/

=== START OF INFORMATION SECTION ===
Model Family: Seagate Barracuda 7200.10 family
Device Model: ST3500630AS
Serial Number: 6QG16BKS
Firmware Version: 3.AAK
User Capacity: 500,107,862,016 bytes
Device is: In smartctl database [for details use: -P show]
ATA Version is: 7
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Mon Jun 1 12:46:25 2009 CDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
See vendor-specific Attribute list for marginal Attributes.

General SMART Values:
Offline data collection status: (0x82) Offline data collection activity
was completed without error.
Auto Offline Data Collection: Enabled.
Self-test execution status: ( 0) The previous self-test routine completed
without error or no self-test has ever
been run.
Total time to complete Offline
data collection: ( 430) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No 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: ( 1) minutes.
Extended self-test routine
recommended polling time: ( 163) minutes.

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x000f 106 093 006 Pre-fail Always - 77490784
3 Spin_Up_Time 0x0003 093 092 000 Pre-fail Always - 0
4 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 141
5 Reallocated_Sector_Ct 0x0033 100 100 036 Pre-fail Always - 1
7 Seek_Error_Rate 0x000f 072 054 030 Pre-fail Always - 69010122065
9 Power_On_Hours 0x0032 085 085 000 Old_age Always - 13209
10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 020 Old_age Always - 133
187 Unknown_Attribute 0x0032 094 094 000 Old_age Always - 6
189 Unknown_Attribute 0x003a 100 100 000 Old_age Always - 0
190 Temperature_Celsius 0x0022 064 038 045 Old_age Always In_the_past 707002404
194 Temperature_Celsius 0x0022 036 062 000 Old_age Always - 36 (Lifetime Min/Max 0/16)
195 Hardware_ECC_Recovered 0x001a 062 058 000 Old_age Always - 129785447
197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0010 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age Always - 4
200 Multi_Zone_Error_Rate 0x0000 100 253 000 Old_age Offline - 0
202 TA_Increase_Count 0x0032 100 253 000 Old_age Always - 0

SMART Error Log Version: 1
ATA Error Count: 10 (device log contains only the most recent five errors)
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 10 occurred at disk power-on lifetime: 13174 hours (548 days + 22 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
-- -- -- -- -- -- --
84 51 97 28 8d 32 e1 Error: ICRC, ABRT 151 sectors at LBA = 0x01328d28 = 20090152

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 d8 e7 8c 32 e1 00 07:16:11.293 READ DMA
c8 00 a8 3f 8c 32 e1 00 07:16:11.238 READ DMA
c8 00 08 8f 8f 59 ee 00 07:16:11.160 READ DMA
c8 00 80 bf e4 2c e1 00 07:16:11.695 READ DMA
c8 00 08 b7 e4 2c e1 00 07:16:11.672 READ DMA

Error 9 occurred at disk power-on lifetime: 13174 hours (548 days + 22 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
-- -- -- -- -- -- --
84 51 27 98 58 0c eb Error: ICRC, ABRT 39 sectors at LBA = 0x0b0c5898 = 185358488

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 58 67 58 0c eb 00 07:16:00.647 READ DMA
c8 00 28 3f 58 0c eb 00 07:16:00.607 READ DMA
c8 00 80 bf 4a 0c eb 00 07:16:00.587 READ DMA
c8 00 48 3f 4e 0c eb 00 07:16:00.581 READ DMA
c8 00 80 3f 36 0c eb 00 07:16:00.560 READ DMA

Error 8 occurred at disk power-on lifetime: 13174 hours (548 days + 22 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
-- -- -- -- -- -- --
84 51 3f 80 4c 0c eb Error: ICRC, ABRT 63 sectors at LBA = 0x0b0c4c80 = 185355392

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 80 3f 4c 0c eb 00 07:15:59.596 READ DMA
c8 00 80 bf 4b 0c eb 00 07:15:59.582 READ DMA
c8 00 80 3f 4b 0c eb 00 07:15:59.572 READ DMA
c8 00 80 bf b0 0d eb 00 07:15:59.532 READ DMA
c8 00 80 3f e3 08 eb 00 07:15:59.456 READ DMA

Error 7 occurred at disk power-on lifetime: 13174 hours (548 days + 22 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
-- -- -- -- -- -- --
84 51 9f 20 5d 0c eb Error: ICRC, ABRT 159 sectors at LBA = 0x0b0c5d20 = 185359648

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 bf 5c 0c eb 00 07:15:57.114 READ DMA
c8 00 80 3f 5c 0c eb 00 07:15:57.052 READ DMA
c8 00 80 3f 3b 0e eb 00 07:15:57.032 READ DMA
c8 00 48 f7 3a 0e eb 00 07:15:57.000 READ DMA
c8 00 20 d7 3a 0e eb 00 07:15:56.996 READ DMA

Error 6 occurred at disk power-on lifetime: 631 hours (26 days + 7 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 ce 92 64 e0 Error: UNC at LBA = 0x006492ce = 6591182

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
25 00 00 3f 91 64 e0 00 04:26:20.329 READ DMA EXT
27 00 00 00 00 00 e0 00 04:26:20.314 READ NATIVE MAX ADDRESS EXT
ec 00 00 00 00 00 a0 02 04:26:20.255 IDENTIFY DEVICE
ef 03 46 00 00 00 a0 02 04:26:20.239 SET FEATURES [Set transfer mode]
27 00 00 00 00 00 e0 00 04:26:18.186 READ NATIVE MAX ADDRESS EXT

SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Extended offline Completed without error 00% 13208 -
# 2 Short offline Aborted by host 60% 13206 -
# 3 Extended offline Completed without error 00% 920 -
# 4 Short offline Completed without error 00% 918 -
# 5 Short offline Interrupted (host reset) 40% 914 -

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.

[grantemsley]

WARNING: I am not an expert with software raid (yet). I know a fair bit but not everything!

According to the SMART info there, your hard drive has had to reallocate one sector (because the old one failed), and has had CRC errors.

IIRC, CRC errors are usually caused by bad cables, so I'd check that.

If you are pretty sure it was just heat problems (and have corrected the heat problem), you can probably keep using that drive. If it contains really important stuff and you don't have backups, I'd backup and replace the drive.

You can use smartctl -t long /dev/whatever to run a full test of the drive, then check the smartctl output again. If the CRC error or reallocated sectors increases after the test - throw the drive out and replace it, because the drive is probably starting to fail.

[wheniwork]

Ok. I ordered a new drive just to be safe. The data is pretty important.

What do you recommend for a good mdadm tutorial on replacing a failed drive and rebuilding the array?

[grantemsley]

I've found http://tldp.org/HOWTO/Software-RAID-HOWTO.html pretty useful, but don't use the raid* commands, they are outdated, use the mdadm commands.

The basic procedure is:
mdadm /dev/md0 -r /dev/sd?? (remove the failed drive)
Pull the drive, add in a replacement. Partition it if your array is on partitions, then:
mdadm /dev/md0 -a /dev/sd?? (add the new drive)

Then "watch cat /proc/mdstat" to watch it rebuild. There are some parameters you can tweak if you want it to rebuild faster (and in the process hurt all other disk IO from the array



echo 200000 > /proc/sys/dev/raid/speed_limit_max
echo 200000 > /proc/sys/dev/raid/speed_limit_min

That will set the max and min rebuild speed to 200MB/s, which should be as fast as possible. The defaults are fairly low IIRC.

[fjgaude]

Here's more links:

http://linux-raid.osdl.org/index.php/Main_Page
http://www.hscripts.com/tutorials/linux-services/mdadm.html

Have fun!

[wheniwork]

Here is the situation now.

We are running Ubuntu Server 8.04 and using Linux Raid (mdadm). We had a drive fail (/dev/sdi1).

The array then automatically removed the drive and degraded the array.

This morning I replaced the physical drive and rebooted the machine.

I partitioned the new drive (now named /dev/sdk1).

Now the array device /dev/md0 is not active. I think this is because the device names got changed so the array is confused now.

Where I am at now is the re assembly of the array. I want to make sure I do it right so nothing is lost. Basically we have a total of 10 drives, 9 are fine, 1 is new. However, the names of the devices changed when I replaced the failed drive so now the array device (/dev/md0) is not active and probably confused (which is why it's not working/mounting).

Any thoughts would be helpful?