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I've been running my server with Ubuntu Server 12.10 for quite some time now and it's been up for about 260 days give or take. This morning we had a power outage which unfortunately did not only reset my uptime, but seems to have destroyed one of my disks in my RAID5 array.

I have four 2TB drives connected to the RAID by the following identifiers:

  • /dev/sda
  • /dev/sdc
  • /dev/sdd
  • /dev/sde

Although, now that I boot my server it spawns a degraded raid and boots me into initramfs, from which I am able to exit using the command exit. I'm now fearing that my one disk has been rendered unusable. This is the output following the command cat /proc/mdstat:

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
    md0 : active raid5 sdc1[1] sdd1[3] sde[5]
    5860535808 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]

From what I understand when search the web, an underscore in the [UUUU] section means that the drive for some reason is not functioning properly. Am I correct? If so, my only logical explanation is that the disk /dev/sda has somehow been rendered unusable. What do you think?

A simple sudo fdisk -l returns the following data about the disk, which looks about normal.

Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00071c7e

Device Boot      Start    End            Blocks        Id    System
/dev/sda1        2048     3907029167     1953513560    fd    Linux raid autodetect

Now I am all out of ideas, and I would really like to get my RAID up and running properly again. Please help me, and if the disk is broken I'll have to go get another tomorrow.

Thanks in advance, Jonathan

EDIT: Here is a full dump of sudo fdisk -l:

Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00071c7e

Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048  3907029167  1953513560   fd  Linux raid autodetect

Disk /dev/sdb: 60.0 GB, 60022480896 bytes
255 heads, 63 sectors/track, 7297 cylinders, total 117231408 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000bab94

Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048      499711      248832   83  Linux
/dev/sdb2          501758   117229567    58363905    5  Extended
/dev/sdb5          501760   117229567    58363904   8e  Linux LVM

Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000bfd1e

Device Boot      Start         End      Blocks   Id  System
/dev/sdc1            2048  3907029167  1953513560   fd  Linux raid autodetect

Disk /dev/sdd: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000291ea

Device Boot      Start         End      Blocks   Id  System
/dev/sdd1            2048  3907029167  1953513560   fd  Linux raid autodetect

WARNING: GPT (GUID Partition Table) detected on '/dev/sde'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sde: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xb177b0f7

Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1  3907029167  1953514583+  ee  GPT
Partition 1 does not start on physical sector boundary.

Disk /dev/md0: 6001.2 GB, 6001188667392 bytes
2 heads, 4 sectors/track, 1465133952 cylinders, total 11721071616 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 524288 bytes / 1572864 bytes
Disk identifier: 0x00000000

Disk /dev/md0 doesn't contain a valid partition table

Also, I tried running sudo mdadm -v --examine /dev/sdX1, where I found an anomality. The command works fine for all the disks except for /dev/sde1, where I had to use /dev/sde and skip the partition. Only then would I get the correct output, which shows a missing disk in the status, .AAA while all the others say AAAA like it should.

To me, it seems like /dev/sde1 is the culprit, but I can't fully judge. I don't dare to disconnect the drives as I don't know what will happen then. What do you think?

EDIT 2: I'm now fairly confident that /dev/sde is the culprit, but I'm not entirely sure.

Please see this paste for more debug info: http://paste.ubuntu.com/6262980/

Thanks in advance!

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