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drbd-user: Re: [DRBD-user] dual primary mode with which FS

Re: [DRBD-user] dual primary mode with which FS

From: Florian Haas <florian.haas_at_nospam>
Date: Tue Mar 23 2010 - 16:27:30 GMT
To: "drbd-user@lists.linbit.com" <drbd-user@lists.linbit.com>

On 2010-03-23 17:08, Digimer wrote:
> From a purely technical view point, Michael isn't wrong. If the second
> node never changes a single block on the DRBD partition, it can't
> technically hurt it. Of course, you'd need to make sure that the node's
> DRBD doesn't try to recover from failures without first fencing the
> other node.
>
> It's not wise, but it's not impossible, either.

man mount:

-r Mount the file system read-only. A synonym is -o ro.

Note that, depending on the filesystem type, state and kernel behavior,
the system may still write to the device. For example, Ext3 or ext4 will
replay its journal if the filesystem is dirty. [...]

This is just a really really bad idea to even attempt, as there are a
myriad ways to mess things up.

I do realize that it's also not impossible to shoot yourself in the head
and survive. That doesn't mean I'll try it out.

Florian

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