Re: Linux software RAID assistance

[NeilBrown <neilb@suse.de>]

On Thu, 10 Feb 2011 16:16:44 +0000 Simon McNair <simonmcnair@gmail.com> wrote:

> 
> Hi all
> 
> I use a 3ware 9500-12 port sata card (JBOD) which will not work without a
> 128mb sodimm.  The sodimm socket is flakey and the result is that the
> machine occasionally crashes.  Yesterday I finally gave in and put 
> together another
> machine so that I can rsync between them.  When I turned the machine
> on today to set up rync, the RAID array was not gone, but corrupted. 
>   Typical...

Presumably the old machine was called 'ubuntu' and the new machine 'proølox'


> 
> I built the array in Aug 2010 using the following command:
> 
> mdadm --create --verbose /dev/md0 --metadata=1.1 --level=5
> --raid-devices=10 /dev/sd{b,c,d,e,f,g,h,i,j,k}1 --chunk=64
> 
> Using LVM, I did the following:
> pvscan
> pvcreate -M2 /dev/md0
> vgcreate lvm-raid /dev/md0
> vgdisplay lvm-raid
> vgscan
> lvscan
> lvcreate -v -l 100%VG -n RAID lvm-raid
> lvdisplay /dev/lvm-raid/lvm0
> 
> I then formatted using:
> mkfs -t ext4 -v -m .1 -b 4096 -E stride=16,stripe-width=144 
> /dev/lvm-raid/RAID
> 
> This worked perfectly since I created the array.  Now mdadm is coming up 
> with
> 
> proxmox:/dev/md# mdadm --assemble --scan --verbose
> mdadm: looking for devices for further assembly
> mdadm: no recogniseable superblock on /dev/md/ubuntu:0

And it seems that ubuntu:0 have been successfully assembled.
It is missing one device for some reason (sdd1) but RAID can cope with that.



> mdadm: cannot open device /dev/dm-2: Device or resource busy
> mdadm: cannot open device /dev/dm-1: Device or resource busy
> mdadm: cannot open device /dev/dm-0: Device or resource busy
> mdadm: cannot open device /dev/sdm1: Device or resource busy
> mdadm: cannot open device /dev/sdm: Device or resource busy
> mdadm: cannot open device /dev/sdl1: Device or resource busy
> mdadm: cannot open device /dev/sdl: Device or resource busy
> mdadm: cannot open device /dev/sdk1: Device or resource busy
> mdadm: cannot open device /dev/sdk: Device or resource busy
> mdadm: cannot open device /dev/sdj1: Device or resource busy
> mdadm: cannot open device /dev/sdj: Device or resource busy
> mdadm: cannot open device /dev/sdh1: Device or resource busy
> mdadm: cannot open device /dev/sdh: Device or resource busy
> mdadm: cannot open device /dev/sdi1: Device or resource busy
> mdadm: cannot open device /dev/sdi: Device or resource busy
> mdadm: cannot open device /dev/sdg1: Device or resource busy
> mdadm: cannot open device /dev/sdg: Device or resource busy
> mdadm: cannot open device /dev/sdf1: Device or resource busy
> mdadm: cannot open device /dev/sdf: Device or resource busy
> mdadm: cannot open device /dev/sde1: Device or resource busy
> mdadm: cannot open device /dev/sde: Device or resource busy
> mdadm: no RAID superblock on /dev/sdd
> mdadm: cannot open device /dev/sda2: Device or resource busy
> mdadm: cannot open device /dev/sda1: Device or resource busy
> mdadm: cannot open device /dev/sda: Device or resource busy
> mdadm: /dev/sdd1 is identified as a member of /dev/md/pro�lox:0, slot 0.
> mdadm: no uptodate device for slot 1 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 2 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 3 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 4 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 5 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 6 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 7 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 8 of /dev/md/pro�lox:0
> mdadm: no uptodate device for slot 9 of /dev/md/pro�lox:0
> mdadm: failed to add /dev/sdd1 to /dev/md/pro�lox:0: Invalid argument
> mdadm: /dev/md/pro�lox:0 assembled from 0 drives - not enough to start
> the array.

This looks like it is *after* to trying the --create command you give
below..  It is best to report things in the order they happen, else you can
confuse people (or get caught out!).


> mdadm: looking for devices for further assembly
> mdadm: no recogniseable superblock on /dev/sdd
> mdadm: No arrays found in config file or automatically
> 
> pvscan and vgscan show nothing.
> 
> So I tried running mdadm --create --verbose /dev/md0 --metadata=1.1
> --level=5 --raid-devices=10 missing /dev/sde1 /dev/sdf1 /dev/sdg1
> /dev/sdh1 /dev/sdi1 /dev/sdj1 /dev/sdk1 /dev/sdl1 /dev/sdm1 --chunk=64
> 
> as it seemed that /dev/sdd1 failed to be added to the array.  This did 
> nothing.

It did not to nothing.  It wrote a superblock to /dev/sdd1 and complained
that it couldn't write to all the others --- didn't it?


> 
> dmesg contains:
> 
> md: invalid superblock checksum on sdd1

I guess that is why sdd1 was missing from 'ubuntu:0'.  Though as I cannot
tell if this happened before or after any of the various things reported
above, it is hard to be sure.


The  real mystery is why 'pvscan' reports nothing.

What about
  pvscan --verbose

or

  blkid -p /dev/md/ubuntu:0

or even

  dd of=/dev/md/ubuntu:0 count=8 | od -c 

??

NeilBrown


--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html