Dan Roberts on 30 Aug 2007 17:43:35 -0000


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Re: [PLUG] How to break a software RAID mirror?


In my instance what would be the specific command to fail sbd
I have never used the mdadm tool..
thanks
dan


On Thu, 2007-08-30 at 13:37 -0400, David Coulson wrote:
> Rather than unplug the disk, it's easier just to fail it using mdadm
> and tell the array that it is gone.
> 
> That said, the array will bitch that it's missing a disk - You can't
> run RAID-1 with only a single disk.
> 
> Not really sure what is trying to be accomplished here, other than
> using sdb for something else - it's not as if there isn't a load of
> unused disk space available. 
> 
> Brian Stempin wrote: 
> > The only raid0 set that I see is /dev/md1.  I don't see that volume
> > mounted anywhere.  Everything else is a raid0, so those volumes are
> > nothing to worry about.  For the sake of testing, I would recommend
> > shutting down the machine, unplugging sdb, and rebooting.  If
> > everything seems to be in order (ie, there's no uses for /deb/md1
> > that I'm unable to see), then you should be good!  Then, it's just a
> > matter of reconfiguring the raid to not complain that sdb isn't
> > present. 
> > 
> > On 8/30/07, Dan Roberts <Daniel.G.Roberts@sanofi-aventis.com>
> > wrote: 
> >         
> >         Hello All
> >         Thanks for the help!
> >         I am running fedora core>>
> >         [droberts@kayak /proc]$ uname -a ;
> >         Linux kayak 2.6.12-1.1381_FC3smp #1 SMP Fri Oct 21 04:03:26
> >         EDT 2005
> >         i686 i686 i386 GNU/Linux
> >         
> >         cat /proc/mdstat 
> >         
> >         Personalities : [raid0] [raid1]
> >         md4 : active raid1 sdb2[1] sda2[0]
> >               25599488 blocks [2/2] [UU]
> >         
> >         md2 : active raid1 sdb3[1] sda3[0]
> >               5116608 blocks [2/2] [UU]
> >         
> >         md3 : active raid1 sdb5[1] sda5[0] 
> >               5116544 blocks [2/2] [UU]
> >         
> >         md1 : active raid0 sdb6[1] sda6[0]
> >               8192896 blocks 64k chunks
> >         
> >         md5 : active raid1 sdb7[1] sda7[0]
> >               29704064 blocks [2/2] [UU]
> >         
> >         md0 : active raid1 sdb1[1] sda1[0] 
> >               2048192 blocks [2/2] [UU]
> >         
> >         unused devices: <none>
> >         [droberts@kayak /proc]$
> >         
> >         So it seems that I am running a mix oF RAID0 and RAID1 on
> >         these two disk
> >         RAIDED sets..
> >         
> >         
> >         The following is how they are mounted on my system when in
> >         use.. 
> >         Filesystem            Size  Used Avail Use% Mounted on
> >         /dev/md0              2.0G  374M  1.5G  21% /
> >         /dev/md5               28G   33M   27G   1% /home2
> >         none                 1004M     0 1004M   0% /dev/shm
> >         /dev/md3              4.9G   34M  4.6G   1% /tmp
> >         /dev/md4               25G  3.2G   20G  15% /usr
> >         /dev/md2              4.9G  190M  4.4G   5% /var
> >         /dev/sdc2              20G  9.8G  8.6G  54% /mnt
> >         
> >         
> >         What would you recommend I do at this point to detach sda
> >         from sdb so 
> >         that I could use disk #2 while still having data preserved
> >         on disk#1?
> >         Remeber that I can still boot my system on disk#3 which
> >         isn't RAIDED to
> >         anyone..
> >         Thanks for any advice!
> >         Dan
> >         
> >         
> >         
> >         ___________________________________________________________________________ 
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> > 
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> ___________________________________________________________________________
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___________________________________________________________________________
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