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I set up a small raid based Ubuntu 11.04 server machine and have just received this email from it. How can i verify or check this ?

Richard

This is an automatically generated mail message from mdadm running on godzilla

A Fail event had been detected on md device /dev/md/0.

It could be related to component device /dev/sda1.

Faithfully yours, etc.

P.S. The /proc/mdstat file currently contains the following:

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sda10 sdb1[1] sdd1[3] sdc1[2] 2927135232 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU] [>....................] check = 2.2% (21655188/975711744) finish=4419.8min speed=3597K/sec

&> cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sda10 sdb1[1] sdd1[3] sdc1[2] 2927135232 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]

unused devices:

cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sda1[0]F sdb1[1]sdd1[3] sdc1[2] 2927135232 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]

unused devices:

Dmsg [775549.274966] md/raid:md0: Disk failure on sda1, disabling device. [775549.274967] md/raid:md0: Operation continuing on 3 devices. [775549.280021] md/raid:md0: read error not correctable (sector 43310408 on sda1
). [775549.280028] md/raid:md0: read error not correctable (sector 43310416 on sda1
). [775549.280031] md/raid:md0: read error not correctable (sector 43310424 on sda1
). [775549.280035] md/raid:md0: read error not correctable (sector 43310432 on sda1
). [775549.280039] md/raid:md0: read error not correctable (sector 43310440 on sda1
). [775549.280043] md/raid:md0: read error not correctable (sector 43310448 on sda1
). [775549.280047] md/raid:md0: read error not correctable (sector 43310456 on sda1
). [775549.280051] md/raid:md0: read error not correctable (sector 43310464 on sda1
). [775549.280055] md/raid:md0: read error not correctable (sector 43310472 on sda1
). [775549.280226] ata7: EH complete [775549.316567] ata7.00: exception Emask 0x0 SAct 0x0 SErr 0x300000 action 0x6 [775549.319133] ata7.00: BMDMA stat 0x45 [775549.321658] ata7: SError: { Dispar BadCRC } [775549.324237] ata7.00: failed command: READ DMA EXT [775549.326754] ata7.00: cmd 25/00:f8:28:ed:94/00:03:02:00:00/e0 tag 0 dma 52019
2 in [775549.326757] res 51/84:48:78:7f:2e/84:00:03:00:00/e0 Emask 0x10 (ATA
bus error) [775549.331806] ata7.00: status: { DRDY ERR } [775549.334350] ata7.00: error: { ICRC ABRT } [775549.336890] ata7: hard resetting link [775549.336895] ata7: nv: skipping hardreset on occupied port [775549.340260] md: md0: data-check done. [775549.804062] ata7: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [775549.844352] ata7.00: configured for UDMA/33 [775549.844390] ata7: EH complete [775549.936450] RAID conf printout: [775549.936456] --- level:5 rd:4 wd:3 [775549.936460] disk 0, o:0, dev:sda1 [775549.936463] disk 1, o:1, dev:sdb1 [775549.936465] disk 2, o:1, dev:sdc1 [775549.936507] disk 3, o:1, dev:sdd1 [775549.936557] RAID conf printout: [775549.936559] --- level:5 rd:4 wd:3 [775549.936562] disk 1, o:1, dev:sdb1 [775549.936564] disk 2, o:1, dev:sdc1 [775549.936567] disk 3, o:1, dev:sdd1

sudo mdadm --detail /dev/md0

/dev/md0: Version : 1.2 Creation Time : Sat Jan 1 14:43:44 2005 Raid Level : raid5 Array Size : 2927135232 (2791.53 GiB 2997.39 GB) Used Dev Size : 975711744 (930.51 GiB 999.13 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent

Update Time : Sun Feb  5 19:17:41 2012
      State : clean, degraded  Active Devices : 3 Working Devices : 3  Failed Devices : 1   Spare Devices : 0

     Layout : left-symmetric
 Chunk Size : 512K

       Name : godzilla:0  (local to host godzilla)
       UUID : 7c2be5e4:25e338e5:b575b8cd:83896caf
     Events : 657

Number   Major   Minor   RaidDevice State
   0       0        0        0      removed
   1       8       17        1      active sync   /dev/sdb1
   2       8       33        2      active sync   /dev/sdc1
   3       8       49        3      active sync   /dev/sdd1

   0       8        1        -      faulty spare   /dev/sda1
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migrated from stackoverflow.com Feb 5 '12 at 18:34

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Also, is there a way to find out which HDD/Sda1 is attached to which SATA port on the MotherBoard ? – DevilCode Feb 5 '12 at 18:15

I'd have a look at the output of 'dmesg' as well as the file /var/log/syslog. There might be hints concerning problems with /dev/sda1.

The hard disk could have crashed but it also could just be a cable that's not plugged in well (SATA cables are just... not that awesome). See whether the device is still online, maybe it is available using a different name like /dev/sde1 or whatever is the next free name in your system. As mentioned, I'd check dmesg/syslog, SMART, too. Maybe the cable just has to be plugged in properly or has to be replaced. In most cases you can re-add the disk to your RAID array - I'd only use those commands if the problem really has to do with broken cables or something comparable, i.e. no "real" hard disk failure.

mdadm --fail /dev/mdX /dev/sdX # set the disk faulty
mdadm -r /dev/mdX /dev/sdX # remove faulty disk
mdadm --re-add /dev/mdX /dev/sdX # re-add disk

Disclaimer: No guarantee, you should have backups, this will rebuild your RAID array - for that time there is no redundancy, etc.

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1  
$ sudo mdadm --fail /dev/md0 /dev/sda1 mdadm: set /dev/sda1 faulty in /dev/md0 $ sudo mdadm -r /dev/md0 /dev/sda1 mdadm: hot removed /dev/sda1 from /dev/md0 $ sudo mdadm --re-add /dev/md0 /dev/sda1 mdadm: --re-add for /dev/sda1 to /dev/md0 is not possible Why whould it not be possible ? – DevilCode Feb 6 '12 at 0:35

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