Re: FEATURE REQUEST: merge MD software raid and LVM in one uniquelayer.

From: david
Date: Wed May 02 2007 - 21:09:38 EST


On Wed, 2 May 2007, Miguel Sousa Filipe wrote:

On 5/2/07, Diego Calleja <diegocg@xxxxxxxxx> wrote:
El Wed, 2 May 2007 20:18:55 +0100, "Miguel Sousa Filipe"
<miguel.filipe@xxxxxxxxx> escribió:

> I find it high irritanting having two kernel interfaces and two
> userland tools that provide the same funcionality, which one should I
> use?

I doubt users care about kernel's design; however the lack of unification
of
userspace tools is a real problem. Just my 2¢.


I believe they do, since the kernels desing obviate the need and use
of several diferent tools (that shouldn't be needed) like for instance
for having raid5 with snapshot and dinamic partition resizing we will
allways need:

md-raid5
lvm
some FS.

This md-raid5 and lvm separation is the evidence of how the kernels
design & API affect usability and userspace tools that the user is
obliged to use. I cannot have those features without "bumping" into
this kernel design issue.
This is also a problem for any developer who tries to improve
usability in this area by creating some unified userland tools to
manipulate MD & LVM. (Imagining myself implementing some userland tool
to create some "storage devices" + mount points.. doesn't seem easy
nor fun..).

why do you care if the userspace tool that does the resizing makes system calls to one layer or to two layers? how would you know?

currently you see that they are seperate becouse you use two different tools to manipulate them, but if it was one tool that manipulated both of them for the common cases you wouldn't know. (this is the point that Diego was trying to make)

David Lang