[CentOS] software raid1 syncing

Sun Jul 5 17:06:13 UTC 2009
Steven Vishoot <sir_funzone at yahoo.com>

----- Original Message ----
> From: "Lucian at lastdot.org" <lucian at lastdot.org>
> To: CentOS mailing list <centos at centos.org>
> Sent: Friday, July 3, 2009 3:45:44 PM
> Subject: Re: [CentOS] software raid1 syncing
> On Fri, Jul 3, 2009 at 9:15 PM, Steven Vishootwrote:
> >
> > hello all,
> >
> > I have a setup that is raid 1 and put the mirrored drive back in and now it is 
> still showing as degraded saying: raid1: raid set md6 active with 1 out of 2 
> mirrors with this message on all the raids.i know i am wrong by saying this but 
> i thought putting in the driving and rebooting would start the re syncing 
> itself. what do i have to do to add this back in, i am so confused with this 
> process.
> >
> > centos 4.x
> >
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> >
> Well, just putting a new disk drive in the place of the bad one
> doesn't cut it. You have to recreate partition table and then add the
> partitions to the drive.
> e.g.
> sda = the old disk in the raid that has not failed
> sdb = the newly added disk
> dd if=/dev/sda of=/dev/sdb bs=512 count=1
> That'll replicate the partition table and mbr to the new disk.
> Then starting addinf the new partitions to the linux raid:
> mdadm -a /dev/sdb1 /dev/md0 and so on, depending what your setup is.
> Do a:
> cat /proc/mdstat and see what partitions are added to which raid.
> Alternatively to a google search for howtos (e.g.
> http://www.gagme.com/greg/linux/raid-lvm.php ) and learn how to manage
> linux raid so you dont fsck up your system.
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Thank you Les & Lucian,

I was able to fix the problem with your help, the first problem was an error between the chair and keyboard. I had forgot to turn the hard drive back on in the bios when i was trying to do some other stuff a while ago, so that caused me some grief and soon as i turned that on i was able to see the drive without having to do the "dd" command. ( i was trying to replace the mirrored drives and knock out the raid but i was not able to get the other drive up and running because i was having so much trouble with samba not working correctly). The second did help me and i was able to sync it up with no problems. 

again thanks