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From: Marc Weber <>
Subject: Re: [linux-lvm] RAID1 mirroring behavior when one disk is dead sometimes - why not just use random numbers ??
Date: Thu, 15 Apr 2021 06:19:50 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

> As far as I know mdadm works the same way. (At least it was working
> like this when this thread happened:
> You can use a similar tactic that was recommended there: Don't
> assemble a degraded RAID1 array without user interaction. You can do
> this by changing the activation mode to complete in lvm.conf.

But then the server doesn't start at all which might also be costly.

The thread says that clock i not reliable eventually due to faulty hardware etc.

*BUT* why isn't there a way to 'stamp' the disks once clock is synced with the internet ?

Let's compare two cases and two solutions.

solution 1:

write dates [date, known-devices] to the active disks

CASE: disk 1 appears sometimes. disk2 would have 'know-devices' disk2 only, so disk1 could be identified as troublesome.

action mirror disk2  to1

CASE: split brain: disk1 appears, reboot disk2 appears, reboot both appear

Dates would be different. -> no mount

Not using the date info at all, thus could be using random numbers which would be solution 2.

I don't have experience how often disks appear sometimes only.

To me it looks like having such strategy above which also could be implemented in user space (but why ?)

would work in more cases very well cause the server would boot more often than not.

Marc Weber

linux-lvm mailing list
read the LVM HOW-TO at

      reply	other threads:[~2021-04-15  4:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13 15:52 [linux-lvm] RAID1 mirroring behavior when one disk is dead sometimes? Marc Weber
2021-04-13 19:44 ` Péter Sárközi
2021-04-15  4:19   ` Marc Weber [this message]

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