SUMMARY: Re: Academic discussion of root disk mirroring -- or is it?

From: Chris W Knox (
Date: Fri Dec 03 1999 - 09:34:44 CST

Thanks to all who responded. The overwhelming majority view
(10 out of over a dozen responses) supports mirroring the swap
device when the root disk is mirrored. The reasons range from
the fact that it doesn't cost much, can't hurt and
[will definitely | should | might] (pick one) avoid a system
panic. I've intentionally induced kernel panics by cat'ing
/dev/null > /dev/swap; this to test a failover system. I
recently tried it with a new E-250 and nothing happened. But
the system was idle.

Real life isn't usually so neat, as points

        Murphys law states that if its gonna happen, it will happen at your
        bussiest time of the year when the machine is pegged and you are home
        sleeping in the dead of winter.. What could mirroring swap hurt? I do.
        Its nice to know that if a disk fails the machine will definatly keep
        running:) I get enough after hours calls for stupid stuff as it is.
        I dont need real problems at 3am.

One minority view characterizes mirroring swap as "superfluous
overhead," but being in a shop that takes the other position
on this point of doctrine, this person holds that view quietly,
to avoid being charged with heresy so I will withhold the name.


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