On Wed, Aug 29, 2012 at 10:14 AM, Michael Stauber <span dir="ltr"><<a href="mailto:mstauber@blueonyx.it" target="_blank">mstauber@blueonyx.it</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Bob,<br>
<br>
> I have a Dell server that I installed 5108. It has two (2) 1GB drives<br>
> and one (1) 2GB disk. When I installed it, I used the option to mirror<br>
> (soft RAID) across the drives but when I did it used all three drives.<br>
> I used "mdadm" to fail and remove the third (2GB) drive. (I did not<br>
> want it part of the root mirror) Now the device shows "clean, degraded"<br>
> when I list it with mdadm:<br>
><br>
> # mdadm --detail /dev/md0<br>
> /dev/md0:<br>
> Version : 1.0<br>
> Creation Time : Fri Jul 20 07:38:36 2012<br>
> Raid Level : raid1<br>
> Array Size : 511988 (500.07 MiB 524.28 MB)<br>
> Used Dev Size : 511988 (500.07 MiB 524.28 MB)<br>
> Raid Devices : 3<br>
> Total Devices : 2<br>
> Persistence : Superblock is persistent<br>
><br>
> Update Time : Tue Aug 28 16:25:57 2012<br>
> State : clean, degraded<br>
> Active Devices : 2<br>
> Working Devices : 2<br>
> Failed Devices : 0<br>
> Spare Devices : 0<br>
><br>
> Name : localhost.localdomain:0<br>
> UUID : 8b68d22d:4566147a:621a50a4:6d016578<br>
> Events : 325<br>
><br>
> Number Major Minor RaidDevice State<br>
> 0 8 1 0 active sync /dev/sda1<br>
> 3 8 17 1 active sync /dev/sdb1<br>
> 2 0 0 2 removed<br>
> #<br>
<br>
I don't know the device of the third disk. But I assume it is /dev/sdc?<br>
<br>
If so, did you really do both steps (fail and remove)? I know, you said<br>
you did, but I'm just making sure. :-)<br>
<br>
mdadm --fail /dev/md0 /dev/sdc1<br>
mdadm --remove /dev/md0 /dev/sdc1<br>
<br>
It may also be helpful to zero the superblock of the removed disk, as it<br>
still contains RAID meta data which mdadm might see:<br>
<br>
mdadm --zero-superblock /dev/sdc<br>
<br>
If you did all those steps, it still could be that the disk is listed in<br>
mdadm.conf, so you'd need to update the conf this way:<br>
<br>
mdadm --detail --scan >> /etc/mdadm.conf<br>
<br>
This appends to /etc/mdadm.conf, so you will have to edit the file<br>
afterwards to remove duplicate lines. Your new ARRAY lines will be at<br>
the end of this file.<br>
<br>
For more information you might want to check this URL:<br>
<br>
<a href="http://www.ducea.com/2009/03/08/mdadm-cheat-sheet/" target="_blank">http://www.ducea.com/2009/03/08/mdadm-cheat-sheet/</a><br>
<span class="HOEnZb"><font color="#888888"><br></font></span></blockquote><div><br>Yea I'm pretty sure I did both steps. And yes the third disk is sdc. I tried the --zero-superblock but it didn't recognize the device:<br>
<br># fdisk -l /dev/sdc<br><br>Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes<br>255 heads, 63 sectors/track, 243201 cylinders<br>Units = cylinders of 16065 * 512 = 8225280 bytes<br>Sector size (logical/physical): 512 bytes / 4096 bytes<br>
I/O size (minimum/optimal): 4096 bytes / 4096 bytes<br>Disk identifier: 0x000c4a89<br><br> Device Boot Start End Blocks Id System<br>/dev/sdc1 1 243201 1953512000+ 83 Linux<br>
# mdadm --zero-superblock /dev/sdc<br>mdadm: Unrecognised md component device - /dev/sdc<br># mdadm --zero-superblock /dev/sdc1<br>mdadm: Unrecognised md component device - /dev/sdc1<br>#<br><br>I compared the contents of mdadm.conf and the output of mdadm --scan and it looks the same:<br>
<br># mdadm.conf written out by anaconda<br>MAILADDR root<br>AUTO +imsm +1.x -all<br>ARRAY /dev/md0 metadata=1.0 level=raid1 num-devices=2 UUID=8b68d22d:4566147a:621a50a4:6d016578<br>ARRAY /dev/md1 metadata=1.1 level=raid1 num-devices=2 UUID=b2bc5b0b:4d3a33ba:39e6a2fb:be3ae14c<br>
# mdadm --detail --scan<br>ARRAY /dev/md1 metadata=1.1 name=localhost.localdomain:1 UUID=b2bc5b0b:4d3a33ba:39e6a2fb:be3ae14c<br>ARRAY /dev/md0 metadata=1.0 name=localhost.localdomain:0 UUID=8b68d22d:4566147a:621a50a4:6d016578<br>
#<br><br>???<br><br></div></div>