[Gllug] To partition or not to partition

[Bruce Richardson]

On Wed, Oct 13, 2010 at 12:44:18AM +0100, Nix wrote:
> >
> > For my personal systems, I do / on the first partition and everything
> > else on LVM.
> 
> For my personal systems, I do *everything* in LVM-atop-RAID, including
> /boot, and use an initramfs to bring it up, bring up the RAID array, and
> so on. I can't live without the resizing flexibility of LVM, and I won't
> live without the ability to survive disk failures. I've had enough of
> depending on a single spinning plate of rust.

I have both the / partition and the LVM ps on mirrored raid, so it's the
same result.

> 
> >               I don't mind sacrificing a few gig to the first partition
> > for one less layer of VFS on the most crucial partition.
> 
> Pretty irrelevant, really, as LVM only interposes *anything* in the
> block I/O path, and that only happens if you're hitting the disk, which
> is much slower than a tiny bit of extra computation could ever be. The
> stuff which is heavily used (e.g /lib and /bin) is in the page cache all
> the time anyway, and page cache accesses don't go through LVM at all
> (well, reads don't: writes obviously do when they get flushed, because
> that hits the block I/O path again).

It's not performance I'm concerned with but robustness.  I'm happier
with fewer things to have to get working before getting to / and using
LVM for everything imporant means the fixed size of the / partition
really doesn't matter.  Can even spin /tmp off if need be.  Have been
bitten on a couple of occasions by the wrong combination of layers on /

> somewhere the distro installer won't smash; swap because, well, there's
> not such a good reason for that because configuring more swap is easy
> and it doesn't matter (within reason) how many swap partitions you've
> got.

But without LVM, how do you achieve the luxury of having as many swap
partitions as you want, whenever you want them?

I used to work with a blithely unthinking clown who would set up LVM on
every server he configured - and then allocate *all* the space on the
VG, right from the start.  Point <-----  ----->>>> Him.

-- 
Bruce

The ice-caps are melting, tra-la-la-la.  All the world is drowning,
tra-la-la-la-la.  -- Tiny Tim.
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