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-   -   RAID1: Urgent.. Two disks out of sync... how to get them back in sync? (http://www.linuxquestions.org/questions/linux-server-73/raid1-urgent-two-disks-out-of-sync-how-to-get-them-back-in-sync-4175481244/)

tkalfaoglu 10-18-2013 12:18 AM

RAID1: Urgent.. Two disks out of sync... how to get them back in sync?
 
Hello. I have a very simple RAID1 system.
Two identical disks sda and sdb, identical partitions on both.

The raid apparently degraded some time ago, and the system kept using /dev/sdb only.

After an fsck, the system booted from /dev/sda..
So, the system went back in time by several months!

I rescued /dev/sdb.. How can I copy stuff from each /dev/sdb partition to /dev/sda?

My intention is to boot from flash, and do a cp -pR from each /dev/sdb partition to its equivalent /dev/sda partition.

Once I collect as much data as possible, I intend to remove sdb to replace it with another drive.

Does that sound good?

Thanks, -turgut

wildwizard 10-18-2013 04:42 AM

You don't want to copy files as that wont fix the RAID flags.

Option 1 both drives in the same place but you can boot sdb
1. You need to boot the system from /dev/sdb
2. You need to check that your running a degraded RAID with only /dev/sdb working
3. You then add /dev/sda back with mdadm --re-add

Option 2 swap the drives so the sdb is sda and boots from there
Similar to option 1 but you swap sda for sdb

re-sync should then be in progress and you can get an indication of the time to completion from /proc/mdstat


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