On Mon, Dec 19, 2011 at 2:45 PM, Ljubomir Ljubojevic office@plnet.rs wrote:
Noticed something funny with an mdadm mirror based raid the other day.
So I had a system disk set to mirror via mdadm.
One of the disks went south at a remote office and since there was no one available to swap out the disk, I thought to leave it for later.
Well, due to work being what is it, this later became a year.
During one of the servers many reboots, much of the data on the system went missing. The logs even showed a gap from the day the disk went bad to the day this reboot occurred.
So picture a gap in the logs of about a year or so.
I first suspected foul play but soon discovered that the previous bad disk in the mirror became functional again and that its data basically put the server back to the time period being a year ago or so.
I had similar thing happening to me just few weeks ago. What happened to me was that raid broke and data was being written only to master disk, that started acting up. So reboot 1 month after the raid breakage brought 1 month old data since that other disk came online and raid master.
I fixed the problem and will better watch out for bad signs. And I am going to reinstall it from 5.6 (now 5.7) to 6.2.
That's not supposed to happen. I've had disks get kicked out and they either resync automatically with the one with the newest data as the master or they don't resync untill you do it manually. Is this a recent regression or have I just been lucky?