Re: [gentoo-user] OT:Choosing a filesystem

[Alan McKinnon <alan.mckinnon@gmail.com>]

On Friday 02 April 2010 14:45:29 Volker Armin Hemmann wrote:
> On Freitag 02 April 2010, meino.cramer@gmx.de wrote:
> > Neil Bothwick <neil@digimed.co.uk> [10-04-02 14:08]:
> > > On Fri, 2 Apr 2010 13:04:53 +0200, meino.cramer@gmx.de wrote:
> > > > only to be sure to have understood everything correctly:
> > > > Suggestion is to create for example one root partition and a swap
> > > > partion. And I will create on big "rest of the disk"-partition.
> > > > The last one will be subdivided with LVM into portions as needed.
> > > 
> > > Yes.
> > > 
> > > > Since the last big partition is big due to physical reasons (not for
> > > > logical one): What will happen, if -- for example -- one portion will
> > > > be not unmounted cleanly and while booting/checking fails to recover?
> > > > Are all others damaged/lost?
> > > 
> > > No, because the failure you describe is at the filesystem level. Even
> > > the volume containing that filesystem will retain integrity, only the
> > > filesystem itself will be corrupted. As you have left free space on
> > > the volume group, you can just create a new volume, format it and copy
> > > over everything you can recover from the broken filesystem before
> > > deleting it.
> > 
> > Hi Neil,
> > 
> > yes, sounds good, very good.
> > Last question: How heavy is the performance impact of such a setup ?
> 
> seriously lvm sounds nice. But it isn't. It easily breaks.

Can you back that up with some facts? I use LVM on many machines and have 
never had it breaks. I'm also quite ruthless on some machines with how I use 
it - manipulating volumes with apparently gay abandon.

I attribute this lack of failure to me understanding how LVm works and using 
it as designed, without trying to be cute and/or clever.

> You want a save setup? Go raid5 or raid6. As a bonus - you can get more
> space if you need it by just adding another disk. And you are not
> depending on some complex stuff to get it working.

The various raid levels do not address the problem that LVM solves - how to 
rapidly create and manipulate sub-volumes. If your /var/log fills up, how 
would you add an extra 10G to it to gain breathing space without using 
something LVM-like (evms is for example LVM-like. So are the native HP-UX 
tools)?

-- 
alan dot mckinnon at gmail dot com