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Re: [LUG] Software RAID-1 on USB drives

 

Grant Sewell wrote:
Hi all,

Just a quick "what if" question...

2 USB drives where periodically rsync is run to duplicate drive 1 onto
drive 2.  Drive 1 is static, drive 2 (should) get removed every evening
and taken off-site.

If the two drives were setup in a software-based RAID-1 (mirror)
configuration, would they automatically reconcile any differences when
drive 2 was re-attached?  If not, how can differences between two
software RAID-0 drives be reconciled?  Is there a command that initiate
the reconciliation?  Can this be added to a udev rule so that when
drive 2 is re-attached the reconciliation happens automatically?

Cheers.
Grant. :)

Not tried it myself (although I had a similar idea), but I believe it might be possible with the mdadm command.

Doing a quick google search came up with this:

http://www.linuxquestions.org/questions/linux-server-73/how-do-i-resync-a-dirty-software-raid1-558876/

I'm guessing that what you need to do is remove the drive and when you reconnect the drive you have to remove it from the raid array and then re-add it.

I'd be interested to know how you get on. Seems like a quick and easy way of getting a machine back up and running.

Rob




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