Re: RAID1 degraded

Adam Goryachev <mailinglists@xxxxxxxxxxxxxxxxxxxxxx> · Tue, 04 Aug 2015 16:02:57 +1000

On 04/08/15 15:51, Hans Malissa wrote:
Thanks a lot for your help!
Rebooting the system didn’t solve the problem, /dev/sdc is still 
nowhere to be found.
So I will have to replace /dev/sdc.
I tried to learn a bit about SRC/ERC from list archives, and it seems 
like my hard drives (1TB Seagate Barracuda’s) don’t support this option:

# smartctl -l scterc /dev/sdb
smartctl 6.0 2012-10-10 r3643 [x86_64-linux-3.7.10-1.45-desktop] (SUSE 
RPM)
Copyright (C) 2002-12, Bruce Allen, Christian Franke, 
www.smartmontools.org <http://www.smartmontools.org>

SCT Error Recovery Control command not supported

/dev/sdc is (was) of exactly the same type, so it wouldn’t support 
SRC/ERC either.
This doesn’t seem to be the problem here, since the drive has just 
disappeared.

Nope that is true, but it is always good to learn about the issue before 
it becomes the problem.

But I will certainly take this into account when buying a replacement 
drive. Any current recommendations about what would work best in a 
RAID1 instead of a 1TB Seagate Barracuda?

My personal preference was WD Black drives, or else Enterprise Black, 
but they were always a lot more expensive. I think WD Red are "RAID 
Certified" these days. (Note, I mostly use SSD now rather than any brand 
HDD, so not a lot of recent experiences).

Just to make sure I understand correctly how to replace /dev/sdc and 
repair my RAID1, the steps to do would be:

 1. Shutdown PC
 2. Replace /dev/sdc
 3. Restart computer
 4. Partition the new /dev/sdc
 5. Run # mdadm —manage /dev/md0 —add /dev/sdc1
 6. Wait for synchronization to finish

Did I get this right? Am I missing anything? Are there additional 
steps (I am backing my data up, anyway) that I can take to maximize my 
chance for success?

Yep, all sounds good. Just make a note of the serial number for sdb 
before you shutdown, and ensure you are removing the correct drive. The 
good thing with RAID1 is that it is difficult to really screw it up, but 
backups are *always* a good idea :)

Regards,
Adam

Thanks a lot,

Hans

On Aug 3, 2015, at 10:33 PM, Adam Goryachev 
<mailinglists@xxxxxxxxxxxxxxxxxxxxxx 
<mailto:mailinglists@xxxxxxxxxxxxxxxxxxxxxx>> wrote:

On 04/08/15 14:16, Hans Malissa wrote:
Thanks a lot for your help!
smartctl yields the following information (details see below): 
/dev/sdb looks ok, but /dev/sdc seems to have quite a problem. 
/dev/sdc seems nonexistent, it’s not even in /dev/ anymore. The disk 
is physically present, but that’s about it.
The kernel logs contain a lot of information; what should I be 
looking for?

The logs should contain information on why or what happened when the 
disk (sdc) vanished. In your case, it does indeed look like sdc has 
failed, so you have a number of options depending on your preference:
1) Simply reboot (including a complete power off) the machine, and 
see if sdc comes back. If it does, do some tests, and then add back 
to the array. If it survives, then carry on as normal.

2) If you are more cautious (and more prepared to spend the money 
rather than risk the data), then purchase a replacement disk, and 
replace sdc with the new disk. Prepare the drive/partition, and add 
it to the raid array.

Please make sure you "Research SCT/ERC on this list"!!! before 
purchasing the replacement drive. It is far better to buy the right 
drive if possible.

Regards,
Adam

Thanks a lot,

Hans

# smartctl -a /dev/sdb
smartctl 6.0 2012-10-10 r3643 [x86_64-linux-3.7.10-1.45-desktop] 
(SUSE RPM)
Copyright (C) 2002-12, Bruce Allen, Christian Franke, 
www.smartmontools.org <http://www.smartmontools.org>

=== START OF INFORMATION SECTION ===
Model Family:     Seagate Barracuda 7200.14 (AF)
Device Model:     ST1000DM003-1ER162
Serial Number:    Z4Y6N2J3
LU WWN Device Id: 5 000c50 07afe5c18
Firmware Version: CC45
User Capacity:    1,000,204,886,016 bytes [1.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2, ACS-3 T13/2161-D revision 3b
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Mon Aug  3 21:52:32 2015 MDT

==> WARNING: A firmware update for this drive may be available,
see the following Seagate web pages:
http://knowledge.seagate.com/articles/en_US/FAQ/207931en
http://knowledge.seagate.com/articles/en_US/FAQ/223651en

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

General SMART Values:
Offline data collection status:  (0x00) Offline data collection activity
                                        was never started.
                                        Auto Offline Data 
Collection: Disabled.
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:                (   80) seconds.
Offline data collection
capabilities:                    (0x73) SMART execute Offline immediate.
                                        Auto Offline data collection 
on/off support.
                                        Suspend Offline collection 
upon new
                                        command.
                                        No 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:        (   1) minutes.
Extended self-test routine
recommended polling time:        ( 105) minutes.
Conveyance self-test routine
recommended polling time:        (   2) minutes.
SCT capabilities:              (0x1085) SCT Status supported.

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   111   100   006    Pre-fail 
 Always       -       39301104
  3 Spin_Up_Time            0x0003   097   097   000    Pre-fail 
 Always       -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age 
  Always       -       20
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail 
 Always       -       0
  7 Seek_Error_Rate         0x000f   063   060   030    Pre-fail 
 Always       -       2152462
  9 Power_On_Hours          0x0032   098   098   000    Old_age 
  Always       -       1872
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail 
 Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age 
  Always       -       20
183 Runtime_Bad_Block       0x0032   100   100   000    Old_age 
  Always       -       0
184 End-to-End_Error        0x0032   100   100   099    Old_age 
  Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age 
  Always       -       0
188 Command_Timeout         0x0032   100   100   000    Old_age 
  Always       -       0 0 0
189 High_Fly_Writes         0x003a   100   100   000    Old_age 
  Always       -       0
190 Airflow_Temperature_Cel 0x0022   068   064   045    Old_age 
  Always       -       32 (Min/Max 26/35)
191 G-Sense_Error_Rate      0x0032   100   100   000    Old_age 
  Always       -       0
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age 
  Always       -       0
193 Load_Cycle_Count        0x0032   093   093   000    Old_age 
  Always       -       15119
194 Temperature_Celsius     0x0022   032   040   000    Old_age 
  Always       -       32 (0 19 0 0 0)
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       -       0
240 Head_Flying_Hours       0x0000   100   253   000    Old_age 
  Offline      -       662h+04m+56.474s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age 
  Offline      -       2212066311
242 Total_LBAs_Read         0x0000   100   253   000    Old_age 
  Offline      -       4204083236

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]

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.

# smartctl -a /dev/sdc
smartctl 6.0 2012-10-10 r3643 [x86_64-linux-3.7.10-1.45-desktop] 
(SUSE RPM)
Copyright (C) 2002-12, Bruce Allen, Christian Franke, 
www.smartmontools.org

Smartctl open device: /dev/sdc failed: No such device

On Aug 3, 2015, at 5:48 PM, Adam Goryachev 
<mailinglists@xxxxxxxxxxxxxxxxxxxxxx> wrote:

On 04/08/15 08:18, Hans Malissa wrote:
Hi everybody,

It looks like one of my disks in my RAID1 just failed:

[SNIP]

Are there any other tests I could run in order to figure out 
what’s going on? It looks like I will have to replace /dev/sdc1 
with a new hard drive. What is the correct procedure to do so 
without loosing my data?

Have a look at dmesg or your system kernel logs for details.
Also, use smartctl to examine what the drive itself thinks.
Also, try to use dd to read/write the drive.

One common scenario is that you haven't configured the timing for 
the drive correctly, and the drive is working perfectly, but didn't 
respond to the kernel quickly enough. Research SCT/ERC on this list

Regards,
Adam
--
Adam Goryachev Website Managers www.websitemanagers.com.au

--
Adam Goryachev Website Managerswww.websitemanagers.com.au 
<http://www.websitemanagers.com.au/>

--
Adam Goryachev Website Managers www.websitemanagers.com.au
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