On Thursday 21 November 2002 15:22, Doug Ledford wrote:

On Thu, Nov 21, 2002 at 09:29:36PM +0000, Alan Cox wrote:

quoted

On Thu, 2002-11-21 at 19:57, Steven Dake wrote:

quoted

Doug,

EVMS integrates all of this stuff together into one cohesive peice of
technology.

But I agree, LVM should be modified to support RAID 1 and RAID 5, or MD
should be modified to support volume management.  Since RAID 1 and RAID
5 are easier to implement, LVM is probably the best place to put all
this stuff.

User space issue. Its about the tools view not about the kernel drivers.

Not entirely true.  You could do everything in user space except online
resize of raid0/4/5 arrays, that requires specific support in the md
modules and it begs for integration between LVM and MD since the MD is
what has to resize the underlying device yet it's the LVM that usually
handles filesystem resizing.

LVM doesn't handle the filesystem resizing, the filesystem tools do. The only 
thing you need is something in user-space to ensure the correct ordering. For 
an expand, the MD device must be expanded first. When that is complete, 
resizefs is called to expand the filesystem.

MD currently doesn't allow resize of RAID 0, 4 or 5, because expanding 
striped devices is way ugly. If it was determined to be possible, the MD 
driver may need additional support to allow online resize. But it is just as 
easy to add this support to MD rather than have to merge MD and DM.

-- 
Kevin Corry
corryk@us.ibm.com
http://evms.sourceforge.net/