Re: Advice on raid/lvm
On Thu, Apr 09, 2009 at 06:59:48PM +1000, Alex Samad (alex@samad.com.au) wrote:
> > > I would create 3 partitions on the 500GB drives
> > > 500M /boot (ext2 or ext3)
> > > 20G / (ext3)
> >
> > Could you explain the rationale behind this?
> /boot can be loaded or and I like to have a resuce image on there just
> incase I stuff something up on /, for the cost of a 1 partition and a
> separate /boot it feel a bit better, when its part of / anything can
> happen to it
Hmm. Are you mounting /boot read-only?
That should work and it'd indeed protect it better.
Otherwise the difference in safety against things
like mistyped rm commands and whatnot would be
marginal, I think.
If you have a concrete example where separate /boot
saved (or would have saved) the day, I'd be interested.
As for rescue image use, maybe it would make sense in some
types of use, but then I'd rather create a separate
partition just for that (and leave it unmounted
in normal use). But if the machine is physically
easily accessible, a removable medium like USB stick
would be better for that.
> I have had to recover to many servers and I like having root on a non
> lvm partition just another layer I don't need it there is a problem.
That's always the tradeoff, yes. LVM gives flexibility at the
cost of increased complexity, and whether it's worth the price
in any given situation, well, depends.
One scenario where I'd consider non-LVM root (and /usr and /var) is
where the machine is located in a hard-to-get-at place, with only less
experienced people present: being able to get the machine up by
talking them trough the hoops up to a point where I could get in with
ssh could indeed be easier then.
> raid1 is easy to deal with when thing go wrong
Well, it has its own issues, but yes, less moving parts than in LVM
(and lvm over raid1 is obviously more complex than either alone).
> and again the cost of it
> is minimal 1 partition slot and managing your data needs
Cost in disk space is minimal, agreed, but there are other costs
caused by the inflexibility it implies.
Anyway, nowadays I usually encrypt / anyway (or rather, encrypt
mdadm devices used as lvm physical volumes and put / in there),
and then there's no choice.
--
Tapani Tarvainen
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